Fluorouracil – Use, Dosage, Side Effects, Interaction

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 74 min read
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Fluorouracil is an antimetabolite fluoropyrimidine analog of the nucleoside pyrimidine with antineoplastic activity. Fluorouracil and its metabolites possess a number of different mechanisms of action. In vivo, fluorouracil is converted to the active metabolite 5-fluoroxyuridine monophosphate (F-UMP); replacing uracil, F-UMP incorporates into RNA and inhibits RNA processing, thereby inhibiting cell growth....

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Article Summary

Fluorouracil is an antimetabolite fluoropyrimidine analog of the nucleoside pyrimidine with antineoplastic activity. Fluorouracil and its metabolites possess a number of different mechanisms of action. In vivo, fluorouracil is converted to the active metabolite 5-fluoroxyuridine monophosphate (F-UMP); replacing uracil, F-UMP incorporates into RNA and inhibits RNA processing, thereby inhibiting cell growth. Another active metabolite, 5-5-fluoro-2'-deoxyuridine-5'-O-monophosphate (F-dUMP), inhibits thymidylate synthase, resulting in the depletion of thymidine triphosphate (TTP), one of the four nucleotide triphosphates used...

Key Takeaways

  • This article explains Mechanism of Action in simple medical language.
  • This article explains Indications in simple medical language.
  • This article explains Contra-Indications in simple medical language.
  • This article explains Dosage in simple medical language.
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Fluorouracil is an antimetabolite fluoropyrimidine analog of the nucleoside pyrimidine with antineoplastic activity. Fluorouracil and its metabolites possess a number of different mechanisms of action. In vivo, fluorouracil is converted to the active metabolite 5-fluoroxyuridine monophosphate (F-UMP); replacing uracil, F-UMP incorporates into RNA and inhibits RNA processing, thereby inhibiting cell growth. Another active metabolite, 5-5-fluoro-2′-deoxyuridine-5′-O-monophosphate (F-dUMP), inhibits thymidylate synthase, resulting in the depletion of thymidine triphosphate (TTP), one of the four nucleotide triphosphates used in the in vivo synthesis of DNA. Other fluorouracil metabolites incorporate into both RNA and DNA; incorporation into RNA results in major effects on both RNA processing and functions.

Fluorouracil (5-FU) is a pyrimidine analog used as an antineoplastic agent to treat multiple solid tumors including colon, rectal, breast, gastric, pancreatic, ovarian, bladder, and liver cancer. Fluorouracil is associated with a low rate of transient serum aminotransferase elevations during therapy and has been implicated in rare cases of clinically apparent acute liver injury.

Mechanism of Action

The precise mechanism of action has not been fully determined, but the main mechanism of fluorouracil is thought to be the binding of the deoxyribonucleotide of the drug (FdUMP) and the folate cofactor, N5–10-methylenetetrahydrofolate, to thymidylate synthase (TS) to form a covalently bound ternary complex. This results in the inhibition of the formation of thymidylate from uracil, which leads to the inhibition of DNA and RNA synthesis and cell death. Fluorouracil can also be incorporated into RNA in place of uridine triphosphate (UTP), producing a fraudulent RNA and interfering with RNA processing and protein synthesis.

or

5-FU requires enzymatic conversion to the nucleotide (ribosylation and phosphorylation) in order to exert its cytotoxic activity. Several routes are available for the formation of the 5′-monophosphate nucleotide (F-UMP) in animal cells. 5-FU may be converted to fluorouridine by uridine phosphorylase and then to F-UMP by uridine kinase, or it may react directly with 5-phosphoribosyl-1-pyrophosphate (PRPP), in a reaction catalyzed by orotate phosphoribosyl transferase, to form F-UMP. Many metabolic pathways are available to F-UMP, including incorporation into RNA. A reaction sequence crucial for antineoplastic activity involves the reduction of the diphosphate nucleotide by the enzyme ribonucleoside diphosphate reductase to the deoxynucleotide level and the eventual formation of 5-fluoro-2′-deoxyuridine-5′-phosphate (F-dUMP). 5-FU also may be converted directly to the deoxyriboside 5-FUdR by the enzyme thymidine phosphorylase and further to F-dUMP, a potent inhibitor of thymidylate synthesis, by thymidine kinase … The interaction between F-dUMP and the enzyme thymidylate synthase leads to the depletion of TTP, a necessary constituent of DNA … The folate cofactor, 5,10-methylenetetrahydrofolate, and F-dUMP form a covalently bound ternary complex with the enzyme. The inhibitory complex resembles the transition state formed during the normal enzymatic reaction when dUMP is converted to thymidylate. Although the physiological complex progresses to the synthesis of thymidylate by transfer of the methylene group and 2 hydrogen atoms from folate to dUMP, this reaction is blocked in the inhibitory complex by the stability of the fluorine carbon bond on F-dUMP; sustained inhibition of the enzyme results

Fluorouracil is an antineoplastic anti-metabolite. Anti-metabolites masquerade as purine or pyrimidine – which become the building blocks of DNA. They prevent these substances from becoming incorporated into DNA during the “S” phase (of the cell cycle), stopping normal development and division. Fluorouracil blocks an enzyme that converts the cytosine nucleotide into the deoxy derivative. In addition, DNA synthesis is further inhibited because Fluorouracil blocks the incorporation of the thymidine nucleotide into the DNA strand.

Indications

  • For the topical treatment of multiple actinic or solar keratoses. In the 5% strength, it is also useful in the treatment of superficial basal cell carcinomas when conventional methods are impractical, such as with multiple lesions or difficult treatment sites. Fluorouracil injection is indicated in the palliative management of some types of cancer, including colon, esophageal, gastric, rectum, breast, biliary tract, stomach, head and neck, cervical, pancreas, renal cell, and carcinoid.
  • Fluorouracil (5-FU) is a pyrimidine analog used as an antineoplastic agent to treat multiple solid tumors including colon, rectal, breast, gastric, pancreatic, ovarian, bladder, and liver cancer.
  • Antimetabolites; Antimetabolites, Antineoplastic; Immunosuppressive Agents
  • Fluorouracil is indicated for the palliative treatment of carcinoma of the colon, rectum, breast, stomach, and pancreas in patients considered to be incurable by surgery or other means.
  • Fluorouracil is also indicated for the treatment of bladder carcinoma, prostatic carcinoma, epithelial ovarian carcinoma, cervical carcinoma, endometrial carcinoma, anal carcinoma, esophageal carcinoma, metastatic tumors of skin carcinoma, hepatoblastoma, and is used by intra-arterial injection for the treatment of hepatic tumors and head and neck tumors.
  • Actinic Keratosis (AK)
  • Breast Cancer
  • Malignant Neoplasm of Colon
  • Malignant Neoplasm of Pancreas
  • Malignant Neoplasm of Stomach
  • Rectal Carcinoma
  • Superficial Basal Cell Carcinoma
  • Verruca (Warts)
  • Hyperkeratotic actinic keratosis

Use in Cancer

Fluorouracil injection is approved to treat:

Fluorouracil is also called 5-FU. Fluorouracil is also being studied in the treatment of other conditions and types of cancer.

Fluorouracil is also available in a topical form. For more information, see the Drug Information Summary for Fluorouracil (Topical).

Contra-Indications

  • Hypersensitivity to the active component or any of the ingredients
  • Pregnancy
  • In patients with dihydropyrimidine dehydrogenase (DPD) enzyme deficiency
  • caloric undernutrition
  • decreased function of bone marrow
  • decreased blood platelets
  • a significant decrease in certain blood clotting cells called platelets
  • low levels of white blood cells
  • low levels of a type of white blood cell called neutrophils
  • angina, a type of chest pain
  • abnormal EKG with QT changes from birth
  • bleeding
  • throat irritation
  • stomatitis, a condition with painful swelling and sores inside the mouth
  • stomach or intestinal ulcer
  • liver problems
  • bleeding of the stomach or intestines
  • decreased kidney function
  • erythrodysesthesia or tingling, pain, redness, and edema in the hands and feet
  • excessive vomiting
  • diarrhea
  • pregnancy
  • a patient who is producing milk and breastfeeding
  • dihydropyrimidine dehydrogenase deficiency
  • spread of malignant cancer to the bone marrow

Dosage

Strengths: 5%; 2%; 1%; 0.5%; 4%

Keratosis

  • 0.5% cream (microsphere formulation): Apply to the affected area once a day where actinic keratosis lesions appear, using enough to cover the entire area with a thin film
  • Duration of therapy: Apply for up to 4 weeks as tolerated; continued treatment up to 4 weeks results in greater ulcer. সহজ বাংলা: শরীরের অস্বাভাবিক দাগ, ক্ষত বা ফোলা অংশ।" data-rx-term="lesion" data-rx-definition="A lesion is an abnormal area of tissue such as a spot, wound, patch, lump, or ulcer. সহজ বাংলা: শরীরের অস্বাভাবিক দাগ, ক্ষত বা ফোলা অংশ।">lesion reduction; local irritation is not markedly increased by extending treatment from 2 to 4 weeks, and is generally resolved within 2 weeks of cessation of therapy 1%, 2%, 5% cream or 2%, 5% solution: Apply 2 times a day in an amount enough to cover the lesions; continue until the inflammatory response reaches the erosion stage, then discontinue use
  • Duration of therapy: 2 to 4 weeks; complete healing of the lesions may not be evident for 1 to 2 months following cessation of therapy
  • The response starts with allergy, infection, or inflammation. সহজ বাংলা: চামড়া লাল হয়ে যাওয়া।" data-rx-term="erythema" data-rx-definition="Erythema means skin redness, often from irritation, allergy, infection, or inflammation. সহজ বাংলা: চামড়া লাল হয়ে যাওয়া।">erythema, usually followed by vesiculation, desquamation, erosion and re-epithelialization.
  • This drug should not be applied near the eyes, nostrils, or mouth.
  • Apply 10 minutes after washing, rinsing, and drying the entire area.
  • This drug may be applied using the fingertips.
  • Immediately after application, the hands should be thoroughly washed.
  • Solar keratoses which do not respond to treatment should be biopsied to confirm the diagnosis.

Basal Cell Carcinoma

  • 5% cream or solution:
  • Apply 2 times a day in an amount sufficient to cover the lesions; continue until the inflammatory response reaches the erosion stage, then discontinue use
  • Duration of therapy: 3 to 6 weeks; however, therapy may be required for as long as 10 to 12 weeks before lesions are obliterated
  • Only a 5% cream or solution is recommended to treat superficial basal cell carcinoma.
  • The response starts with allergy, infection, or inflammation. সহজ বাংলা: চামড়া লাল হয়ে যাওয়া।" data-rx-term="erythema" data-rx-definition="Erythema means skin redness, often from irritation, allergy, infection, or inflammation. সহজ বাংলা: চামড়া লাল হয়ে যাওয়া।">erythema, usually followed by vesiculation, desquamation, erosion and re-epithelialization.

Administration advice:

  • Apply with a nonmetal applicator or glove; if applied with the fingers, the hands should be washed immediately afterward.
  • Avoid contact with mucous membranes, eyelids, eyes, nostrils, or mouth.
  • Avoid prolonged exposure to ultraviolet light or sunlight.
  • Avoid occlusive dressings unless clinically indicated.

General:

  • Deep, penetrating, or nodular basal cell and squamous cell carcinomas do not usually respond to this drug; it should be used only as a palliative therapy in such cases where no other form of treatment is possible.
  • The 0.5%, 1%, and 2% strengths should not be used in the treatment of basal cell carcinoma.
  • When this drug is applied to a ulcer. সহজ বাংলা: শরীরের অস্বাভাবিক দাগ, ক্ষত বা ফোলা অংশ।" data-rx-term="lesion" data-rx-definition="A lesion is an abnormal area of tissue such as a spot, wound, patch, lump, or ulcer. সহজ বাংলা: শরীরের অস্বাভাবিক দাগ, ক্ষত বা ফোলা অংশ।">lesion, a response occurs with the following sequence: allergy, infection, or inflammation. সহজ বাংলা: চামড়া লাল হয়ে যাওয়া।" data-rx-term="erythema" data-rx-definition="Erythema means skin redness, often from irritation, allergy, infection, or inflammation. সহজ বাংলা: চামড়া লাল হয়ে যাওয়া।">erythema, usually followed by vesiculation, desquamation, erosion, and reepithelialization

Side Effects

The Most Common

  • burning, crusting, redness,
  • discoloration, irritation, pain,
  • itching, rash, or
  • soreness at the site of application
  • severe stomach pain
  • bloody diarrhea
  • vomiting
  • fever
  • chills
  • severe red skin rash
  • Local pain
  • Itchiness
  • Burning
  • Stinging
  • Crusting
  • Weeping
  • Dermatitis
  • Photosensitivity

More Common

  • Nausea
  • Vomiting
  • Diarrhea (see below for details)
  • Mucositis
  • Headache
  • Myelosuppression (see below for details)
  • Alopecia (hair loss)
  • Photosensitivity
  • Hand-foot syndrome
  • Maculopapular eruption
  • Itch
  • Cardiotoxicity (see below for details)
  • Persistent hiccups
  • Mood disorders (irritability, anxiety, depression)
  • skin pain, itching, burning, or irritation;
  • skin darkening or scarring;
  • skin redness and swelling; or
  • small blood vessels under the skin.

Rare

  • Oesophagitis
  • GI ulceration and bleeding
  • Proctitis
  • Nail disorders
  • Vein pigmentation
  • Confusion
  • Cerebellar syndrome
  • Encephalopathy
  • Visual changes
  • Photophobia
  • Lacrimation (the expulsion of tears without any emotional or physiologic reason)
  • Anaphylaxis
  • Allergic reactions
  • Fever without signs of infection

Drug Interaction

Pregnancy and lactation

AU TGA pregnancy category: D
US FDA pregnancy category: Not assigned.

Pregnancy

This drug can harm a developing fetus when administered to a pregnant woman. No adequate and well-controlled studies have been conducted in pregnant women with either topical or parenteral forms. One birth defect (ventricular septal defect) and cases of miscarriage have been reported when this drug was applied to mucous membrane areas. Multiple birth defects have been reported in the fetus of a patient treated with the IV formulation.

Lactation

Most sources consider breastfeeding to be contraindicated during maternal antineoplastic drug therapy. It might be possible to breastfeed safely during intermittent therapy with an appropriate period of breastfeeding abstinence, but the duration of abstinence is not clear.

How should this medicine be used?

Fluorouracil comes as a solution and a cream to apply to the skin. It is usually applied to the affected areas twice a day. To help you remember to use fluorouracil, apply it around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Use fluorouracil exactly as directed. Do not apply more or less of it or apply it more often than prescribed by your doctor.

If you are using fluorouracil to treat actinic or solar keratoses, you should continue using it until the lesions start to peel off. This usually takes about 2 to 4 weeks. However, the lesions may not be completely healed until 1 or 2 months after you stop using fluorouracil.

If you are using fluorouracil to treat basal cell carcinoma, you should continue using it until the lesions are gone. This usually takes at least 3 to 6 weeks, but may take as long as 10 to 12 weeks.

During the first few weeks of treatment, the skin lesions and surrounding areas will feel irritated and look red, swollen, and scaly. This is a sign that fluorouracil is working. Do not stop using fluorouracil unless your doctor has told you to do so.

Apply fluorouracil cream with a nonmetal applicator, a glove, or your finger. If you apply fluorouracil cream with your finger, be sure to wash your hands well immediately afterward. Do not cover the treated areas with a bandage or dressing unless your doctor tells you to.

Do not apply fluorouracil cream or topical solution to the eyelids or the eyes, nose, or mouth.

What special precautions should I follow?

Before using fluorouracil,

  • tell your doctor and pharmacist if you are allergic to fluorouracil or any other medications.
  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking, especially other topical medications. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor if you have or have ever had dihydropyrimidine dehydrogenase (DPD) enzyme deficiency (a lack of a naturally occurring enzyme in your body).
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while using fluorouracil , call your doctor immediately. Fluorouracil can harm the fetus.
  • plan to avoid unnecessary or prolonged exposure to sunlight and UV light (such as tanning booths) and to wear protective clothing, sunglasses, and sunscreen. Fluorouracil may make your skin sensitive to sunlight.

References

 

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Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

  • Write when the problem started and how it changed.
  • Bring old prescriptions, investigation reports, and current medicines.
  • Write allergies, pregnancy status, diabetes, kidney/liver disease, and major past illnesses.
  • Bring one family member if the patient is weak, elderly, confused, or a child.

Questions to ask

  • What is the most likely cause of my symptoms?
  • Which danger signs mean I should go to hospital quickly?
  • Which tests are necessary now, and which can wait?
  • How should I take medicines safely and what side effects should I watch for?
  • When should I come for follow-up?

Tests to discuss

  • Vital signs: temperature, pulse, blood pressure, oxygen saturation
  • Basic physical examination by a clinician
  • CBC, urine test, blood sugar, or imaging only when clinically needed

Avoid these mistakes

  • Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
  • Do not hide pregnancy, kidney disease, ulcer, allergy, or blood thinner use.
  • Do not delay emergency care when danger signs are present.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

  • Avoid heavy lifting, sudden bending, and prolonged bed rest.
  • Use comfortable posture and gentle movement as tolerated.
  • Discuss physiotherapy, X-ray, or MRI only when clinically needed.

OTC medicine safety

  • For mild back pain, pain-relief medicine may be discussed with a doctor or pharmacist.
  • Avoid repeated painkiller use if you have kidney disease, stomach ulcer, uncontrolled blood pressure, or are taking blood thinners.

Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
  • Do not use steroid tablets or injections casually for quick relief.
  • Do not delay emergency care because of home remedies.

Get urgent help if

  • Back pain with leg weakness, numbness around private area, loss of urine/stool control, fever, cancer history, or major injury needs urgent care.
Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

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Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Medicine doctor / pediatrician for children / qualified clinician
Tests to discuss with doctor
  • Temperature chart and hydration assessment
  • CBC with platelet count if fever persists or dengue/other infection is possible
  • Urine test, malaria/dengue tests, chest evaluation, or blood culture only when clinically indicated
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?
  • Do I need antibiotics, or is this more likely viral?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: Fluorouracil – Use, Dosage, Side Effects, Interaction

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

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Emergency first: Severe chest pain, breathing trouble, unconsciousness, stroke signs, severe injury, heavy bleeding, or rapidly worsening symptoms need urgent local medical care now.

Frequently Asked Questions

Mechanism of Action The precise mechanism of action has not been fully determined, but the main mechanism of fluorouracil is thought to be the binding of the deoxyribonucleotide of the drug (FdUMP) and the folate cofactor, N5–10-methylenetetrahydrofolate, to thymidylate synthase (TS) to form a covalently bound ternary complex. This results in the inhibition of the formation of thymidylate from uracil, which leads to the inhibition of DNA and RNA synthesis and cell death. Fluorouracil can also be incorporated into RNA in place of uridine triphosphate (UTP), producing a fraudulent RNA and interfering with RNA processing and protein synthesis. or 5-FU requires enzymatic conversion to the nucleotide (ribosylation and phosphorylation) in order to exert its cytotoxic activity. Several routes are available for the formation of the 5'-monophosphate nucleotide (F-UMP) in animal cells. 5-FU may be converted to fluorouridine by uridine phosphorylase and then to F-UMP by uridine kinase, or it may react directly with 5-phosphoribosyl-1-pyrophosphate (PRPP), in a reaction catalyzed by orotate phosphoribosyl transferase, to form F-UMP. Many metabolic pathways are available to F-UMP, including incorporation into RNA. A reaction sequence crucial for antineoplastic activity involves the reduction of the diphosphate nucleotide by the enzyme ribonucleoside diphosphate reductase to the deoxynucleotide level and the eventual formation of 5-fluoro-2'-deoxyuridine-5'-phosphate (F-dUMP). 5-FU also may be converted directly to the deoxyriboside 5-FUdR by the enzyme thymidine phosphorylase and further to F-dUMP, a potent inhibitor of thymidylate synthesis, by thymidine kinase ... The interaction between F-dUMP and the enzyme thymidylate synthase leads to the depletion of TTP, a necessary constituent of DNA ... The folate cofactor, 5,10-methylenetetrahydrofolate, and F-dUMP form a covalently bound ternary complex with the enzyme. The inhibitory complex resembles the transition state formed during the normal enzymatic reaction when dUMP is converted to thymidylate. Although the physiological complex progresses to the synthesis of thymidylate by transfer of the methylene group and 2 hydrogen atoms from folate to dUMP, this reaction is blocked in the inhibitory complex by the stability of the fluorine carbon bond on F-dUMP; sustained inhibition of the enzyme results Fluorouracil is an antineoplastic anti-metabolite. Anti-metabolites masquerade as purine or pyrimidine - which become the building blocks of DNA. They prevent these substances from becoming incorporated into DNA during the "S" phase (of the cell cycle), stopping normal development and division. Fluorouracil blocks an enzyme that converts the cytosine nucleotide into the deoxy derivative. In addition, DNA synthesis is further inhibited because Fluorouracil blocks the incorporation of the thymidine nucleotide into the DNA strand. Indications For the topical treatment of multiple actinic or solar keratoses. In the 5% strength, it is also useful in the treatment of superficial basal cell carcinomas when conventional methods are impractical, such as with multiple lesions or difficult treatment sites. Fluorouracil injection is indicated in the palliative management of some types of cancer, including colon, esophageal, gastric, rectum, breast, biliary tract, stomach, head and neck, cervical, pancreas, renal cell, and carcinoid. Fluorouracil (5-FU) is a pyrimidine analog used as an antineoplastic agent to treat multiple solid tumors including colon, rectal, breast, gastric, pancreatic, ovarian, bladder, and liver cancer. Antimetabolites; Antimetabolites, Antineoplastic; Immunosuppressive Agents Fluorouracil is indicated for the palliative treatment of carcinoma of the colon, rectum, breast, stomach, and pancreas in patients considered to be incurable by surgery or other means. Fluorouracil is also indicated for the treatment of bladder carcinoma, prostatic carcinoma, epithelial ovarian carcinoma, cervical carcinoma, endometrial carcinoma, anal carcinoma, esophageal carcinoma, metastatic tumors of skin carcinoma, hepatoblastoma, and is used by intra-arterial injection for the treatment of hepatic tumors and head and neck tumors. Actinic Keratosis (AK) Breast Cancer Malignant Neoplasm of Colon Malignant Neoplasm of Pancreas Malignant Neoplasm of Stomach Rectal Carcinoma Superficial Basal Cell Carcinoma Verruca (Warts) Hyperkeratotic actinic keratosis Use in Cancer Fluorouracil injection is approved to treat: Breast cancer. Colorectal cancer. Gastric (stomach) cancer. Pancreatic cancer. Fluorouracil is also called 5-FU. Fluorouracil is also being studied in the treatment of other conditions and types of cancer. Fluorouracil is also available in a topical form. For more information, see the Drug Information Summary for Fluorouracil (Topical). Contra-Indications Hypersensitivity to the active component or any of the ingredients Pregnancy In patients with dihydropyrimidine dehydrogenase (DPD) enzyme deficiency caloric undernutrition decreased function of bone marrow decreased blood platelets a significant decrease in certain blood clotting cells called platelets low levels of white blood cells low levels of a type of white blood cell called neutrophils angina, a type of chest pain abnormal EKG with QT changes from birth bleeding throat irritation stomatitis, a condition with painful swelling and sores inside the mouth stomach or intestinal ulcer liver problems bleeding of the stomach or intestines decreased kidney function erythrodysesthesia or tingling, pain, redness, and edema in the hands and feet excessive vomiting diarrhea pregnancy a patient who is producing milk and breastfeeding dihydropyrimidine dehydrogenase deficiency spread of malignant cancer to the bone marrow Dosage Strengths: 5%; 2%; 1%; 0.5%; 4% Keratosis 0.5% cream (microsphere formulation): Apply to the affected area once a day where actinic keratosis lesions appear, using enough to cover the entire area with a thin film Duration of therapy: Apply for up to 4 weeks as tolerated; continued treatment up to 4 weeks results in greater lesion reduction; local irritation is not markedly increased by extending treatment from 2 to 4 weeks, and is generally resolved within 2 weeks of cessation of therapy 1%, 2%, 5% cream or 2%, 5% solution: Apply 2 times a day in an amount enough to cover the lesions; continue until the inflammatory response reaches the erosion stage, then discontinue use Duration of therapy: 2 to 4 weeks; complete healing of the lesions may not be evident for 1 to 2 months following cessation of therapy The response starts with erythema, usually followed by vesiculation, desquamation, erosion and re-epithelialization. This drug should not be applied near the eyes, nostrils, or mouth. Apply 10 minutes after washing, rinsing, and drying the entire area. This drug may be applied using the fingertips. Immediately after application, the hands should be thoroughly washed. Solar keratoses which do not respond to treatment should be biopsied to confirm the diagnosis. Basal Cell Carcinoma 5% cream or solution: Apply 2 times a day in an amount sufficient to cover the lesions; continue until the inflammatory response reaches the erosion stage, then discontinue use Duration of therapy: 3 to 6 weeks; however, therapy may be required for as long as 10 to 12 weeks before lesions are obliterated Only a 5% cream or solution is recommended to treat superficial basal cell carcinoma. The response starts with erythema, usually followed by vesiculation, desquamation, erosion and re-epithelialization. Administration advice: Apply with a nonmetal applicator or glove; if applied with the fingers, the hands should be washed immediately afterward. Avoid contact with mucous membranes, eyelids, eyes, nostrils, or mouth. Avoid prolonged exposure to ultraviolet light or sunlight. Avoid occlusive dressings unless clinically indicated. General: Deep, penetrating, or nodular basal cell and squamous cell carcinomas do not usually respond to this drug; it should be used only as a palliative therapy in such cases where no other form of treatment is possible. The 0.5%, 1%, and 2% strengths should not be used in the treatment of basal cell carcinoma. When this drug is applied to a lesion, a response occurs with the following sequence: erythema, usually followed by vesiculation, desquamation, erosion, and reepithelialization Side Effects The Most Common burning, crusting, redness, discoloration, irritation, pain, itching, rash, or soreness at the site of application severe stomach pain bloody diarrhea vomiting fever chills severe red skin rash Local pain Itchiness Burning Stinging Crusting Weeping Dermatitis Photosensitivity More Common Nausea Vomiting Diarrhea (see below for details) Mucositis Headache Myelosuppression (see below for details) Alopecia (hair loss) Photosensitivity Hand-foot syndrome Maculopapular eruption Itch Cardiotoxicity (see below for details) Persistent hiccups Mood disorders (irritability, anxiety, depression) skin pain, itching, burning, or irritation; skin darkening or scarring; skin redness and swelling; or small blood vessels under the skin. Rare Oesophagitis GI ulceration and bleeding Proctitis Nail disorders Vein pigmentation Confusion Cerebellar syndrome Encephalopathy Visual changes Photophobia Lacrimation (the expulsion of tears without any emotional or physiologic reason) Anaphylaxis Allergic reactions Fever without signs of infection Drug Interaction DRUG INTERACTION Abametapir The serum concentration of Fluorouracil can be increased when it is combined with Abametapir. Abatacept The metabolism of Fluorouracil can be increased when combined with Abatacept. Abciximab The risk or severity of bleeding can be increased when Abciximab is combined with Fluorouracil. Abemaciclib Abemaciclib may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Abiraterone The serum concentration of Fluorouracil can be increased when it is combined with Abiraterone. Abrocitinib The metabolism of Abrocitinib can be decreased when combined with Fluorouracil. Acenocoumarol The metabolism of Acenocoumarol can be decreased when combined with Fluorouracil. Acetaminophen The metabolism of Fluorouracil can be decreased when combined with Acetaminophen. Acetohexamide The metabolism of Acetohexamide can be decreased when combined with Fluorouracil. Acetyldigitoxin Acetyldigitoxin may decrease the cardiotoxic activities of Fluorouracil. Acetylsalicylic acid The metabolism of Acetylsalicylic acid can be decreased when combined with Fluorouracil. Acrivastine The risk or severity of QTc prolongation can be increased when Acrivastine is combined with Fluorouracil. Acyclovir The metabolism of Acyclovir can be decreased when combined with Fluorouracil. Adalimumab The metabolism of Fluorouracil can be increased when combined with Adalimumab. Adenosine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Adenosine. Adenovirus type 7 The risk or severity of infection can be increased when Adenovirus type 7 vaccine live is combined with Fluorouracil. Afatinib Afatinib may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Agomelatine The metabolism of Agomelatine can be decreased when combined with Fluorouracil. Ajmaline The risk or severity of QTc prolongation can be increased when Ajmaline is combined with Fluorouracil. Albendazole The metabolism of Fluorouracil can be increased when combined with Albendazole. Aldesleukin The risk or severity of adverse effects can be increased when Aldesleukin is combined with Fluorouracil. Alectinib Alectinib may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Alefacept The risk or severity of adverse effects can be increased when Alefacept is combined with Fluorouracil. Alemtuzumab The risk or severity of adverse effects can be increased when Alemtuzumab is combined with Fluorouracil. Alfuzosin The risk or severity of QTc prolongation can be increased when Alfuzosin is combined with Fluorouracil. Alimemazine The risk or severity of QTc prolongation can be increased when Alimemazine is combined with Fluorouracil. Allantoin The therapeutic efficacy of Allantoin can be decreased when used in combination with Fluorouracil. Allogeneic processed The therapeutic efficacy of Allogeneic processed thymus tissue can be decreased when used in combination with Fluorouracil. Allopurinol The risk or severity of adverse effects can be increased when Allopurinol is combined with Fluorouracil. Almotriptan The metabolism of Fluorouracil can be decreased when combined with Almotriptan. Alosetron The metabolism of Fluorouracil can be decreased when combined with Alosetron. Alpelisib The metabolism of Fluorouracil can be decreased when combined with Alpelisib. Alteplase The risk or severity of bleeding can be increased when Alteplase is combined with Fluorouracil. Altretamine The risk or severity of adverse effects can be increased when Altretamine is combined with Fluorouracil. Amantadine The risk or severity of QTc prolongation can be increased when Amantadine is combined with Fluorouracil. Amifampridine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Amifampridine. Aminophenazone The metabolism of Fluorouracil can be decreased when combined with Aminophenazone. Aminophylline The metabolism of Aminophylline can be decreased when combined with Fluorouracil. Amiodarone The metabolism of Amiodarone can be decreased when combined with Fluorouracil. Amisulpride The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Amisulpride. Amitriptyline The metabolism of Fluorouracil can be decreased when combined with Amitriptyline. Amodiaquine The metabolism of Fluorouracil can be decreased when combined with Amodiaquine. Amoxapine The risk or severity of QTc prolongation can be increased when Amoxapine is combined with Fluorouracil. Amphetamine The metabolism of Fluorouracil can be decreased when combined with Amphetamine. Amprenavir The metabolism of Amprenavir can be decreased when combined with Fluorouracil. Amsacrine The risk or severity of adverse effects can be increased when Amsacrine is combined with Fluorouracil. Anagrelide The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Anagrelide. Anakinra The metabolism of Fluorouracil can be increased when combined with Anakinra. Anastrozole The metabolism of Fluorouracil can be decreased when combined with Anastrozole. Ancrod The risk or severity of bleeding can be increased when Ancrod is combined with Fluorouracil. Anifrolumab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Anifrolumab. Anistreplase The risk or severity of bleeding can be increased when Anistreplase is combined with Fluorouracil. Antazoline The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Antazoline. Anthrax immune The therapeutic efficacy of Anthrax immune globulin human can be decreased when used in combination with Fluorouracil. Anthrax vaccine The risk or severity of infection can be increased when Anthrax vaccine is combined with Fluorouracil. Antilymphocyte The risk or severity of adverse effects can be increased when Fluorouracil is combined with Antilymphocyte immunoglobulin (horse). Antipyrine The metabolism of Fluorouracil can be decreased when combined with Antipyrine. Antithrombin Alfa The risk or severity of bleeding can be increased when Antithrombin Alfa is combined with Fluorouracil. Antithrombin III human The risk or severity of bleeding can be increased when Antithrombin III human is combined with Fluorouracil. Antithymocyte The risk or severity of adverse effects can be increased when Antithymocyte immunoglobulin (rabbit) is combined with Fluorouracil. Apalutamide The metabolism of Fluorouracil can be decreased when combined with Apalutamide. Apixaban The metabolism of Fluorouracil can be decreased when combined with Apixaban. Apomorphine The metabolism of Fluorouracil can be decreased when combined with Apomorphine. Apremilast The metabolism of Fluorouracil can be increased when combined with Apremilast. Ardeparin The risk or severity of bleeding can be increased when Ardeparin is combined with Fluorouracil. Arformoterol The metabolism of Fluorouracil can be decreased when combined with Arformoterol. Argatroban The risk or severity of bleeding can be increased when Argatroban is combined with Fluorouracil. Aripiprazole The risk or severity of QTc prolongation can be increased when Aripiprazole is combined with Fluorouracil. Aripiprazole lauroxil The risk or severity of QTc prolongation can be increased when Aripiprazole lauroxil is combined with Fluorouracil. Armodafinil The metabolism of Fluorouracil can be increased when combined with Armodafinil. Arsenic trioxide The risk or severity of adverse effects can be increased when Fluorouracil is combined with Arsenic trioxide. Artemether The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Artemether. Articaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Articaine. Asenapine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Asenapine. Astemizole The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Astemizole. COVID-19 Vaccine The therapeutic efficacy of AstraZeneca COVID-19 Vaccine can be decreased when used in combination with Fluorouracil. Asunaprevir The metabolism of Fluorouracil can be decreased when combined with Asunaprevir. Atazanavir The metabolism of Fluorouracil can be decreased when combined with Atazanavir. Atomoxetine The risk or severity of QTc prolongation can be increased when Atomoxetine is combined with Fluorouracil. Atorvastatin The metabolism of Fluorouracil can be decreased when combined with Atorvastatin. Atropine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Atropine. Avanafil Avanafil may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Avapritinib The metabolism of Avapritinib can be decreased when combined with Fluorouracil. Avatrombopag The metabolism of Fluorouracil can be increased when combined with Avatrombopag. Axitinib The metabolism of Axitinib can be decreased when combined with Fluorouracil. Azacitidine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Azacitidine. Azatadine The risk or severity of QTc prolongation can be increased when Azatadine is combined with Fluorouracil. Azathioprine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Azathioprine. Azelastine The metabolism of Fluorouracil can be decreased when combined with Azelastine. Azithromycin The risk or severity of QTc prolongation can be increased when Azithromycin is combined with Fluorouracil. Belinostat The risk or severity of adverse effects can be increased when Fluorouracil is combined with Belinostat. Belumosudil The risk or severity of adverse effects can be increased when Fluorouracil is combined with Belumosudil. Bemiparin The risk or severity of bleeding can be increased when Bemiparin is combined with Fluorouracil. Bendamustine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Bendamustine. Bendroflumethiazide The risk or severity of neutropenia and thrombocytopenia can be increased when Bendroflumethiazide is combined with Fluorouracil. Benzatropine The risk or severity of QTc prolongation can be increased when Benzatropine is combined with Fluorouracil. Benzocaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Benzocaine. Benzthiazide The risk or severity of neutropenia and thrombocytopenia can be increased when Benzthiazide is combined with Fluorouracil. Benzyl alcohol The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Benzyl alcohol. Bepridil The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Bepridil. Berotralstat The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Berotralstat. Betamethasone The metabolism of Fluorouracil can be increased when combined with Betamethasone. Betaxolol The metabolism of Fluorouracil can be decreased when combined with Betaxolol. Betrixaban The risk or severity of bleeding can be increased when Betrixaban is combined with Fluorouracil. Bevacizumab The risk or severity of cardiotoxicity can be increased when Bevacizumab is combined with Fluorouracil. Bexarotene The metabolism of Fluorouracil can be decreased when combined with Bexarotene. Bezafibrate The metabolism of Fluorouracil can be decreased when combined with Bezafibrate. Bilastine The risk or severity of QTc prolongation can be increased when Bilastine is combined with Fluorouracil. Bimekizumab The metabolism of Fluorouracil can be increased when combined with Bimekizumab. Binimetinib The metabolism of Binimetinib can be decreased when combined with Fluorouracil. Bivalirudin The risk or severity of bleeding can be increased when Bivalirudin is combined with Fluorouracil. Bleomycin The risk or severity of adverse effects can be increased when Bleomycin is combined with Fluorouracil. Blinatumomab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Blinatumomab. Bordetella pertussis The therapeutic efficacy of Bordetella pertussis toxoid antigen (formaldehyde, glutaraldehyde inactivated) can be decreased when used in combination with Fluorouracil. Bortezomib The risk or severity of adverse effects can be increased when Bortezomib is combined with Fluorouracil. Bosentan The metabolism of Bosentan can be decreased when combined with Fluorouracil. Bosutinib The metabolism of Fluorouracil can be decreased when combined with Bosutinib. Brentuximab vedotin The risk or severity of adverse effects can be increased when Fluorouracil is combined with Brentuximab vedotin. Bretylium The risk or severity of QTc prolongation can be increased when Bretylium is combined with Fluorouracil. Brigatinib The metabolism of Brigatinib can be decreased when combined with Fluorouracil. Brivaracetam The metabolism of Brivaracetam can be decreased when combined with Fluorouracil. Brodalumab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Brodalumab. Bromazepam The metabolism of Bromazepam can be decreased when combined with Fluorouracil. Bromotheophylline The metabolism of Bromotheophylline can be decreased when combined with Fluorouracil. Brompheniramine The risk or severity of QTc prolongation can be increased when Brompheniramine is combined with Fluorouracil. Buclizine The risk or severity of QTc prolongation can be increased when Buclizine is combined with Fluorouracil. Budesonide The risk or severity of adverse effects can be increased when Fluorouracil is combined with Budesonide. Bupivacaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Bupivacaine. Buprenorphine The metabolism of Fluorouracil can be decreased when combined with Buprenorphine. Bupropion The metabolism of Bupropion can be decreased when combined with Fluorouracil. Buserelin The risk or severity of QTc prolongation can be increased when Buserelin is combined with Fluorouracil. Busulfan The risk or severity of adverse effects can be increased when Fluorouracil is combined with Busulfan. Butacaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Butacaine. Butamben The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Butamben. Butriptyline The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Butriptyline. Cabazitaxel The metabolism of Cabazitaxel can be decreased when combined with Fluorouracil. Cabozantinib The metabolism of Fluorouracil can be decreased when combined with Cabozantinib. Caffeine The metabolism of Fluorouracil can be decreased when combined with Caffeine. Canakinumab The metabolism of Fluorouracil can be increased when combined with Canakinumab. Candesartan cilexetil The metabolism of Fluorouracil can be decreased when combined with Candesartan cilexetil. Cangrelor The risk or severity of bleeding can be increased when Cangrelor is combined with Fluorouracil. Cannabidiol The metabolism of Fluorouracil can be decreased when combined with Cannabidiol. Capecitabine The metabolism of Capecitabine can be decreased when combined with Fluorouracil. Caplacizumab The risk or severity of bleeding can be increased when Caplacizumab is combined with Fluorouracil. Capmatinib The serum concentration of Fluorouracil can be increased when it is combined with Capmatinib. Capsaicin The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Capsaicin. Carbamazepine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Carbamazepine. Carbinoxamine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Carbinoxamine. Carboplatin The risk or severity of adverse effects can be increased when Fluorouracil is combined with Carboplatin. Carfilzomib The risk or severity of adverse effects can be increased when Fluorouracil is combined with Carfilzomib. Carmustine The risk or severity of adverse effects can be increased when Carmustine is combined with Fluorouracil. Carvedilol The metabolism of Carvedilol can be decreased when combined with Fluorouracil. Celecoxib The metabolism of Fluorouracil can be decreased when combined with Celecoxib. Celiprolol The risk or severity of QTc prolongation can be increased when Celiprolol is combined with Fluorouracil. Cenobamate The metabolism of Fluorouracil can be increased when combined with Cenobamate. Ceritinib The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Ceritinib. Cerivastatin The metabolism of Fluorouracil can be decreased when combined with Cerivastatin. Certolizumab pegol The metabolism of Fluorouracil can be increased when combined with Certolizumab pegol. Cetirizine The risk or severity of QTc prolongation can be increased when Cetirizine is combined with Fluorouracil. Chlorambucil The risk or severity of adverse effects can be increased when Chlorambucil is combined with Fluorouracil. Chloramphenicol The risk or severity of adverse effects can be increased when Chloramphenicol is combined with Fluorouracil. Chlorcyclizine The risk or severity of QTc prolongation can be increased when Chlorcyclizine is combined with Fluorouracil. Chloroprocaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Chloroprocaine. Chloroquine The metabolism of Fluorouracil can be decreased when combined with Chloroquine. Chlorothiazide The risk or severity of neutropenia and thrombocytopenia can be increased when Chlorothiazide is combined with Fluorouracil. Chlorpheniramine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Chlorpheniramine. Chlorpromazine The risk or severity of QTc prolongation can be increased when Chlorpromazine is combined with Fluorouracil. Chlorpropamide The metabolism of Chlorpropamide can be decreased when combined with Fluorouracil. Chlorprothixene The risk or severity of QTc prolongation can be increased when Chlorprothixene is combined with Fluorouracil. Chlorzoxazone The metabolism of Fluorouracil can be decreased when combined with Chlorzoxazone. Cholesterol Cholesterol may increase the excretion rate of Fluorouracil which could result in a lower serum level and potentially a reduction in efficacy. Ciclesonide The risk or severity of adverse effects can be increased when Fluorouracil is combined with Ciclesonide. Cilostazol The metabolism of Cilostazol can be decreased when combined with Fluorouracil. Cimetidine The serum concentration of Fluorouracil can be increased when it is combined with Cimetidine. Cinacalcet The metabolism of Cinacalcet can be decreased when combined with Fluorouracil. Cinchocaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Cinchocaine. Cinnarizine The metabolism of Fluorouracil can be decreased when combined with Cinnarizine. Cinoxacin The metabolism of Fluorouracil can be decreased when combined with Cinoxacin. Ciprofloxacin The metabolism of Fluorouracil can be decreased when combined with Ciprofloxacin. Cisapride The metabolism of Fluorouracil can be decreased when combined with Cisapride. Cisplatin The risk or severity of adverse effects can be increased when Cisplatin is combined with Fluorouracil. Citalopram The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Citalopram. Cladribine The risk or severity of adverse effects can be increased when Cladribine is combined with Fluorouracil. Clarithromycin The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Clarithromycin. Clemastine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Clemastine. Clobetasol propionate The risk or severity of adverse effects can be increased when Fluorouracil is combined with Clobetasol propionate. Clofarabine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Clofarabine. Clofazimine Clofazimine may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Clofibrate The metabolism of Fluorouracil can be decreased when combined with Clofibrate. Clomipramine The metabolism of Clomipramine can be decreased when combined with Fluorouracil. Clonidine The metabolism of Clonidine can be decreased when combined with Fluorouracil. Clopidogrel The metabolism of Fluorouracil can be decreased when combined with Clopidogrel. Clostridium tetani The therapeutic efficacy of Clostridium tetani toxoid antigen (formaldehyde inactivated) can be decreased when used in combination with Fluorouracil. Clozapine The risk or severity of neutropenia can be increased when Fluorouracil is combined with Clozapine. Cobicistat Cobicistat may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Cocaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Cocaine. Conjugated estrogens The metabolism of Fluorouracil can be decreased when combined with Conjugated estrogens. Corticotropin The risk or severity of adverse effects can be increased when Fluorouracil is combined with Corticotropin. Cortisone acetate The risk or severity of adverse effects can be increased when Fluorouracil is combined with Cortisone acetate. Corynebacterium The therapeutic efficacy of Corynebacterium diphtheriae toxoid antigen (formaldehyde inactivated) can be decreased when used in combination with Fluorouracil. Crizotinib The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Crizotinib. Curcumin The metabolism of Fluorouracil can be decreased when combined with Curcumin. Cyanocobalamin The therapeutic efficacy of Cyanocobalamin can be decreased when used in combination with Fluorouracil. Cyclizine The risk or severity of QTc prolongation can be increased when Cyclizine is combined with Fluorouracil. Cyclobenzaprine The metabolism of Cyclobenzaprine can be decreased when combined with Fluorouracil. Cyclopenthiazide The risk or severity of neutropenia and thrombocytopenia can be increased when Cyclopenthiazide is combined with Fluorouracil. Cyclophosphamide The metabolism of Fluorouracil can be increased when combined with Cyclophosphamide. Cyclosporine Fluorouracil may increase the immunosuppressive activities of Cyclosporine. Cyclothiazide The risk or severity of neutropenia and thrombocytopenia can be increased when Cyclothiazide is combined with Fluorouracil. Cyproheptadine The risk or severity of QTc prolongation can be increased when Cyproheptadine is combined with Fluorouracil. Cyproterone acetate The metabolism of Fluorouracil can be increased when combined with Cyproterone acetate. Cytarabine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Cytarabine. Dabigatran The risk or severity of bleeding can be increased when Dabigatran is combined with Fluorouracil. Dabigatran etexilate The risk or severity of bleeding can be increased when Dabigatran etexilate is combined with Fluorouracil. Dabrafenib The serum concentration of Fluorouracil can be decreased when it is combined with Dabrafenib. Dacarbazine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Dacarbazine. Daclatasvir Daclatasvir may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Dacomitinib The metabolism of Dacomitinib can be decreased when combined with Fluorouracil. Dactinomycin The risk or severity of adverse effects can be increased when Fluorouracil is combined with Dactinomycin. Dalteparin The risk or severity of bleeding can be increased when Dalteparin is combined with Fluorouracil. Danaparoid The risk or severity of bleeding can be increased when Danaparoid is combined with Fluorouracil. Dantrolene The therapeutic efficacy of Dantrolene can be decreased when used in combination with Fluorouracil. Dapagliflozin The metabolism of Fluorouracil can be decreased when combined with Dapagliflozin. Dapsone The metabolism of Fluorouracil can be decreased when combined with Dapsone. Darbepoetin alfa The risk or severity of Thrombosis can be increased when Darbepoetin alfa is combined with Fluorouracil. Darolutamide The serum concentration of Fluorouracil can be increased when it is combined with Darolutamide. Dasabuvir The metabolism of Fluorouracil can be decreased when combined with Dasabuvir. Dasatinib The risk or severity of adverse effects can be increased when Fluorouracil is combined with Dasatinib. Daunorubicin The risk or severity of adverse effects can be increased when Fluorouracil is combined with Daunorubicin. Decitabine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Decitabine. Deferasirox The serum concentration of Fluorouracil can be increased when it is combined with Deferasirox. Defibrotide The risk or severity of bleeding can be increased when Defibrotide is combined with Fluorouracil. Deflazacort The risk or severity of adverse effects can be increased when Fluorouracil is combined with Deflazacort. Degarelix The risk or severity of QTc prolongation can be increased when Degarelix is combined with Fluorouracil. Delafloxacin The risk or severity of QTc prolongation can be increased when Delafloxacin is combined with Fluorouracil. Delamanid Fluorouracil may increase the QTc-prolonging activities of Delamanid. Denosumab The risk or severity of adverse effects can be increased when Denosumab is combined with Fluorouracil. Desflurane The risk or severity of QTc prolongation can be increased when Desflurane is combined with Fluorouracil. Desipramine The risk or severity of QTc prolongation can be increased when Desipramine is combined with Fluorouracil. Desirudin The risk or severity of bleeding can be increased when Desirudin is combined with Fluorouracil. Deslanoside Deslanoside may decrease the cardiotoxic activities of Fluorouracil. Desloratadine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Desloratadine. Desogestrel The metabolism of Desogestrel can be decreased when combined with Fluorouracil. Desoximetasone The risk or severity of adverse effects can be increased when Fluorouracil is combined with Desoximetasone. Deucravacitinib The risk or severity of adverse effects can be increased when Fluorouracil is combined with Deucravacitinib. Deutetrabenazine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Deutetrabenazine. Dexamethasone The metabolism of Fluorouracil can be increased when combined with Dexamethasone. Dexamethasone acetate Dexamethasone acetate may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Dexbrompheniramine The risk or severity of QTc prolongation can be increased when Dexbrompheniramine is combined with Fluorouracil. Dexchlorpheniramine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Dexchlorpheniramine maleate. Dexfenfluramine The metabolism of Dexfenfluramine can be decreased when combined with Fluorouracil. Dexibuprofen The metabolism of Fluorouracil can be decreased when combined with Dexibuprofen. Dexmedetomidine The metabolism of Fluorouracil can be decreased when combined with Dexmedetomidine. Dexrazoxane The risk or severity of adverse effects can be increased when Dexrazoxane is combined with Fluorouracil. Dextran The risk or severity of bleeding can be increased when Dextran is combined with Fluorouracil. Dextromethorphan The metabolism of Dextromethorphan can be decreased when combined with Fluorouracil. Diacerein The metabolism of Fluorouracil can be decreased when combined with Diacerein. Diazepam The metabolism of Diazepam can be decreased when combined with Fluorouracil. Diclofenac The metabolism of Fluorouracil can be decreased when combined with Diclofenac. Dicoumarol The metabolism of Dicoumarol can be decreased when combined with Fluorouracil. Diethylstilbestrol The metabolism of Fluorouracil can be decreased when combined with Diethylstilbestrol. Difluocortolone The risk or severity of adverse effects can be increased when Fluorouracil is combined with Difluocortolone. Digitoxin Digitoxin may decrease the cardiotoxic activities of Fluorouracil. Digoxin Digoxin may decrease the cardiotoxic activities of Fluorouracil. Dihydralazine The metabolism of Fluorouracil can be decreased when combined with Dihydralazine. Diltiazem The metabolism of Fluorouracil can be decreased when combined with Diltiazem. Dimenhydrinate The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Dimenhydrinate. Dimethyl fumarate The risk or severity of adverse effects can be increased when Fluorouracil is combined with Dimethyl fumarate. Dinutuximab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Dinutuximab. Diphenhydramine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Diphenhydramine. Dipyridamole The risk or severity of bleeding can be increased when Dipyridamole is combined with Fluorouracil. Diroximel fumarate The risk or severity of adverse effects can be increased when Fluorouracil is combined with Diroximel fumarate. Disopyramide The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Disopyramide. Disulfiram The risk or severity of QTc prolongation can be increased when Disulfiram is combined with Fluorouracil. Docetaxel The risk or severity of adverse effects can be increased when Fluorouracil is combined with Docetaxel. Doconexent The metabolism of Doconexent can be decreased when combined with Fluorouracil. Dofetilide The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Dofetilide. Dolasetron The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Dolasetron. Domperidone The metabolism of Fluorouracil can be decreased when combined with Domperidone. Donepezil The metabolism of Donepezil can be decreased when combined with Fluorouracil. Dosulepin The metabolism of Fluorouracil can be decreased when combined with Dosulepin. Doxazosin The metabolism of Doxazosin can be decreased when combined with Fluorouracil. Doxepin The metabolism of Doxepin can be decreased when combined with Fluorouracil. Doxorubicin The risk or severity of adverse effects can be increased when Fluorouracil is combined with Doxorubicin. Doxylamine The risk or severity of QTc prolongation can be increased when Doxylamine is combined with Fluorouracil. Dronabinol The serum concentration of Dronabinol can be increased when it is combined with Fluorouracil. Dronedarone The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Dronedarone. Droperidol The risk or severity of QTc prolongation can be increased when Droperidol is combined with Fluorouracil. Drotrecogin alfa The risk or severity of bleeding can be increased when Drotrecogin alfa is combined with Fluorouracil. Duloxetine The metabolism of Duloxetine can be decreased when combined with Fluorouracil. Dyclonine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Dyclonine. Ebastine The risk or severity of QTc prolongation can be increased when Ebastine is combined with Fluorouracil. Ebola Zaire vaccine The therapeutic efficacy of Ebola Zaire vaccine (live, attenuated) can be decreased when used in combination with Fluorouracil. Eculizumab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Eculizumab. Edetic acid The risk or severity of bleeding can be increased when Edetic acid is combined with Fluorouracil. Edoxaban The risk or severity of bleeding can be increased when Edoxaban is combined with Fluorouracil. Efalizumab The risk or severity of adverse effects can be increased when Efalizumab is combined with Fluorouracil. Efavirenz The metabolism of Fluorouracil can be decreased when combined with Efavirenz. Elagolix The metabolism of Fluorouracil can be decreased when combined with Elagolix. Elbasvir Elbasvir may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Eletriptan The metabolism of Fluorouracil can be increased when combined with Eletriptan. Eliglustat The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Eliglustat. Eltrombopag The metabolism of Fluorouracil can be decreased when combined with Eltrombopag. Emapalumab The metabolism of Fluorouracil can be increased when combined with Emapalumab. Emedastine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Emedastine. Enasidenib The metabolism of Fluorouracil can be decreased when combined with Enasidenib. Encainide The risk or severity of QTc prolongation can be increased when Encainide is combined with Fluorouracil. Encorafenib The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Encorafenib. Enoxacin The metabolism of Fluorouracil can be decreased when combined with Enoxacin. Enoxaparin The risk or severity of bleeding can be increased when Enoxaparin is combined with Fluorouracil. Entecavir The metabolism of Fluorouracil can be decreased when combined with Entecavir. Entrectinib The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Entrectinib. Enzalutamide The metabolism of Fluorouracil can be decreased when combined with Enzalutamide. Epinastine The risk or severity of QTc prolongation can be increased when Epinastine is combined with Fluorouracil. Epirubicin The risk or severity of adverse effects can be increased when Epirubicin is combined with Fluorouracil. Epoprostenol The risk or severity of bleeding can be increased when Epoprostenol is combined with Fluorouracil. Eptifibatide The risk or severity of bleeding can be increased when Eptifibatide is combined with Fluorouracil. Erdafitinib The metabolism of Erdafitinib can be decreased when combined with Fluorouracil. Eribulin The risk or severity of adverse effects can be increased when Fluorouracil is combined with Eribulin. Erlotinib The metabolism of Fluorouracil can be decreased when combined with Erlotinib. Erythromycin The risk or severity of QTc prolongation can be increased when Erythromycin is combined with Fluorouracil. Erythropoietin The risk or severity of Thrombosis can be increased when Erythropoietin is combined with Fluorouracil. Escitalopram The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Escitalopram. Esketamine The metabolism of Esketamine can be decreased when combined with Fluorouracil. Esmolol The risk or severity of QTc prolongation can be increased when Esmolol is combined with Fluorouracil. Estradiol The metabolism of Fluorouracil can be decreased when combined with Estradiol. Estradiol acetate The metabolism of Fluorouracil can be decreased when combined with Estradiol acetate. Estradiol benzoate The metabolism of Fluorouracil can be decreased when combined with Estradiol benzoate. Estradiol cypionate The metabolism of Fluorouracil can be decreased when combined with Estradiol cypionate. Estradiol dienanthate The metabolism of Fluorouracil can be decreased when combined with Estradiol dienanthate. Estradiol valerate The metabolism of Fluorouracil can be decreased when combined with Estradiol valerate. Estramustine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Estramustine. Estrone sulfate The metabolism of Fluorouracil can be decreased when combined with Estrone sulfate. Eszopiclone The metabolism of Fluorouracil can be decreased when combined with Eszopiclone. Etanercept The metabolism of Fluorouracil can be increased when combined with Etanercept. Ethambutol The metabolism of Fluorouracil can be decreased when combined with Ethambutol. Ethanol The metabolism of Ethanol can be decreased when combined with Fluorouracil. Ethinylestradiol The metabolism of Fluorouracil can be decreased when combined with Ethinylestradiol. Ethosuximide The risk or severity of QTc prolongation can be increased when Ethosuximide is combined with Fluorouracil. Ethotoin The therapeutic efficacy of Ethotoin can be decreased when used in combination with Fluorouracil. Ethyl chloride The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Ethyl chloride. Etidocaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Etidocaine. Etodolac The metabolism of Etodolac can be decreased when combined with Fluorouracil. Etoposide The risk or severity of adverse effects can be increased when Fluorouracil is combined with Etoposide. Etoricoxib The metabolism of Etoricoxib can be decreased when combined with Fluorouracil. Etravirine The metabolism of Etravirine can be decreased when combined with Fluorouracil. Everolimus The risk or severity of adverse effects can be increased when Fluorouracil is combined with Everolimus. Ezogabine The risk or severity of QTc prolongation can be increased when Ezogabine is combined with Fluorouracil. Famotidine The metabolism of Fluorouracil can be decreased when combined with Famotidine. Famtozinameran The therapeutic efficacy of Famtozinameran can be decreased when used in combination with Fluorouracil. Favipiravir The metabolism of Fluorouracil can be decreased when combined with Favipiravir. Febuxostat The excretion of Fluorouracil can be decreased when combined with Febuxostat. Fedratinib Fedratinib may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Felbamate The risk or severity of QTc prolongation can be increased when Felbamate is combined with Fluorouracil. Felodipine The metabolism of Fluorouracil can be decreased when combined with Felodipine. Fenfluramine The metabolism of Fenfluramine can be decreased when combined with Fluorouracil. Fenofibrate The metabolism of Fluorouracil can be decreased when combined with Fenofibrate. Fexinidazole The risk or severity of adverse effects can be increased when Fluorouracil is combined with Fexinidazole. Filgotinib The serum concentration of Fluorouracil can be increased when it is combined with Filgotinib. Finerenone The metabolism of Fluorouracil can be decreased when combined with Finerenone. Fingolimod Fluorouracil may increase the immunosuppressive activities of Fingolimod. Flecainide The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Flecainide. Floxuridine The risk or severity of adverse effects can be increased when Floxuridine is combined with Fluorouracil. Fluconazole The risk or severity of QTc prolongation can be increased when Fluconazole is combined with Fluorouracil. Flucytosine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Flucytosine. Fludarabine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Fludarabine. Fludrocortisone The risk or severity of adverse effects can be increased when Fluorouracil is combined with Fludrocortisone. Fluindione The metabolism of Fluindione can be decreased when combined with Fluorouracil. Flunarizine The metabolism of Fluorouracil can be decreased when combined with Flunarizine. Flunisolide The risk or severity of adverse effects can be increased when Flunisolide is combined with Fluorouracil. Flunitrazepam The metabolism of Fluorouracil can be decreased when combined with Flunitrazepam. Fluocinolone acetonide The risk or severity of adverse effects can be increased when Fluorouracil is combined with Fluocinolone acetonide. Fluocinonide The risk or severity of adverse effects can be increased when Fluorouracil is combined with Fluocinonide. Fluocortolone The risk or severity of adverse effects can be increased when Fluorouracil is combined with Fluocortolone. Fluorometholone The risk or severity of adverse effects can be increased when Fluorometholone is combined with Fluorouracil. Fluoxetine The risk or severity of QTc prolongation can be increased when Fluoxetine is combined with Fluorouracil. Flupentixol The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Flupentixol. Fluprednisolone The risk or severity of adverse effects can be increased when Fluorouracil is combined with Fluprednisolone. Flurazepam The metabolism of Fluorouracil can be decreased when combined with Flurazepam. Flurbiprofen The metabolism of Flurbiprofen can be decreased when combined with Fluorouracil. Fluspirilene The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Fluspirilene. Flutamide The metabolism of Fluorouracil can be decreased when combined with Flutamide. Fluticasone The metabolism of Fluorouracil can be decreased when combined with Fluticasone. Fluticasone furoate The metabolism of Fluorouracil can be decreased when combined with Fluticasone furoate. Fluticasone propionate The metabolism of Fluorouracil can be decreased when combined with Fluticasone propionate. Fluvastatin The metabolism of Fluorouracil can be decreased when combined with Fluvastatin. Fluvoxamine The metabolism of Fluorouracil can be decreased when combined with Fluvoxamine. Folic acid The risk or severity of adverse effects can be increased when Folic acid is combined with Fluorouracil. Fomepizole The metabolism of Fluorouracil can be decreased when combined with Fomepizole. Fondaparinux The risk or severity of bleeding can be increased when Fondaparinux is combined with Fluorouracil. Fostamatinib Fostamatinib may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Fostemsavir Fostemsavir may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Frovatriptan The metabolism of Frovatriptan can be decreased when combined with Fluorouracil. Furosemide The therapeutic efficacy of Furosemide can be decreased when used in combination with Fluorouracil. Fusidic acid Fusidic acid may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Gadobenic acid The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Gadobenic acid. Galantamine The risk or severity of QTc prolongation can be increased when Galantamine is combined with Fluorouracil. Gallium nitrate The risk or severity of adverse effects can be increased when Fluorouracil is combined with Gallium nitrate. Gatifloxacin The metabolism of Fluorouracil can be decreased when combined with Gatifloxacin. Gefitinib Gefitinib may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Gemcitabine The serum concentration of Fluorouracil can be increased when it is combined with Gemcitabine. Gemfibrozil The metabolism of Fluorouracil can be decreased when combined with Gemfibrozil. Gemifloxacin The metabolism of Fluorouracil can be decreased when combined with Gemifloxacin. Gemtuzumab ozogamicin The risk or severity of adverse effects can be increased when Gemtuzumab ozogamicin is combined with Fluorouracil. Gilteritinib The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Gilteritinib. Gimeracil The serum concentration of Fluorouracil can be increased when it is combined with Gimeracil. Givosiran The serum concentration of Fluorouracil can be increased when it is combined with Givosiran. Glasdegib The metabolism of Fluorouracil can be decreased when combined with Glasdegib. Glatiramer The risk or severity of adverse effects can be increased when Fluorouracil is combined with Glatiramer. Glecaprevir Glecaprevir may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Gliclazide The metabolism of Gliclazide can be decreased when combined with Fluorouracil. Glimepiride The metabolism of Glimepiride can be decreased when combined with Fluorouracil. Glipizide The metabolism of Glipizide can be decreased when combined with Fluorouracil. Gliquidone The metabolism of Gliquidone can be decreased when combined with Fluorouracil. Glyburide The metabolism of Glyburide can be decreased when combined with Fluorouracil. Golimumab The metabolism of Fluorouracil can be increased when combined with Golimumab. Goserelin The risk or severity of QTc prolongation can be increased when Goserelin is combined with Fluorouracil. Granisetron The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Granisetron. Grazoprevir Grazoprevir may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Grepafloxacin The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Grepafloxacin. Guanabenz The metabolism of Guanabenz can be decreased when combined with Fluorouracil. Guselkumab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Guselkumab. Haemophilus The therapeutic efficacy of Haemophilus influenzae type B strain 20752 capsular polysaccharide tetanus toxoid conjugate antigen can be decreased when used in combination with Fluorouracil. Halofantrine The metabolism of Fluorouracil can be decreased when combined with Halofantrine. Haloperidol The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Haloperidol. Halothane The metabolism of Fluorouracil can be decreased when combined with Halothane. Heparin The therapeutic efficacy of Heparin can be decreased when used in combination with Fluorouracil. Hepatitis A Vaccine The therapeutic efficacy of Hepatitis A Vaccine can be decreased when used in combination with Fluorouracil. Hepatitis B Vaccine The therapeutic efficacy of Hepatitis B Vaccine (Recombinant) can be decreased when used in combination with Fluorouracil. Histrelin The risk or severity of QTc prolongation can be increased when Histrelin is combined with Fluorouracil. Human adenovirus The risk or severity of infection can be increased when Human adenovirus e serotype 4 strain cl-68578 antigen is combined with Fluorouracil. Hydrochlorothiazide The risk or severity of QTc prolongation can be increased when Hydrochlorothiazide is combined with Fluorouracil. Hydrocortisone The metabolism of Fluorouracil can be increased when combined with Hydrocortisone. Hydrocortisone acetate The risk or severity of adverse effects can be increased when Fluorouracil is combined with Hydrocortisone acetate. Hydrocortisone butyrate The risk or severity of adverse effects can be increased when Fluorouracil is combined with Hydrocortisone butyrate. Hydrocortisone succinate The risk or severity of adverse effects can be increased when Fluorouracil is combined with Hydrocortisone succinate. Hydroflumethiazide The risk or severity of neutropenia and thrombocytopenia can be increased when Hydroflumethiazide is combined with Fluorouracil. Hydromorphone The metabolism of Hydromorphone can be decreased when combined with Fluorouracil. Hydroxychloroquine The metabolism of Fluorouracil can be decreased when combined with Hydroxychloroquine. Hydroxyurea The risk or severity of adverse effects can be increased when Fluorouracil is combined with Hydroxyurea. Hydroxyzine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Hydroxyzine. Hyoscyamine The risk or severity of QTc prolongation can be increased when Hyoscyamine is combined with Fluorouracil. Ibandronate The risk or severity of QTc prolongation can be increased when Ibandronate is combined with Fluorouracil. Ibritumomab tiuxetan The risk or severity of adverse effects can be increased when Ibritumomab tiuxetan is combined with Fluorouracil. Ibrutinib The risk or severity of adverse effects can be increased when Fluorouracil is combined with Ibrutinib. Ibuprofen The metabolism of Fluorouracil can be decreased when combined with Ibuprofen. Ibutilide The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Ibutilide. Icosapent ethyl The risk or severity of bleeding can be increased when Icosapent ethyl is combined with Fluorouracil. Idarubicin The risk or severity of adverse effects can be increased when Fluorouracil is combined with Idarubicin. Idelalisib The risk or severity of adverse effects can be increased when Fluorouracil is combined with Idelalisib. Ifosfamide The metabolism of Fluorouracil can be increased when combined with Ifosfamide. Iloperidone The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Iloperidone. Iloprost The risk or severity of bleeding can be increased when Iloprost is combined with Fluorouracil. Imatinib The metabolism of Fluorouracil can be decreased when combined with Imatinib. Imipramine The metabolism of Fluorouracil can be decreased when combined with Imipramine. Indacaterol The risk or severity of QTc prolongation can be increased when Indacaterol is combined with Fluorouracil. Indapamide The risk or severity of QTc prolongation can be increased when Indapamide is combined with Fluorouracil. Indomethacin The risk or severity of adverse effects can be increased when Indomethacin is combined with Fluorouracil. Inebilizumab The risk or severity of infection can be increased when Fluorouracil is combined with Inebilizumab. Infliximab The metabolism of Fluorouracil can be increased when combined with Infliximab. Methsuximide The risk or severity of QTc prolongation can be increased when Methsuximide is combined with Fluorouracil. Methylene blue The metabolism of Fluorouracil can be decreased when combined with Methylene blue. Methylprednisolone The risk or severity of adverse effects can be increased when Fluorouracil is combined with Methylprednisolone. Metoclopramide The metabolism of Metoclopramide can be decreased when combined with Fluorouracil. Metreleptin The metabolism of Fluorouracil can be increased when combined with Metreleptin. Metronidazole The serum concentration of Fluorouracil can be increased when it is combined with Metronidazole. Metyrapone The metabolism of Fluorouracil can be decreased when combined with Metyrapone. Mexiletine The metabolism of Fluorouracil can be decreased when combined with Mexiletine. Mianserin The metabolism of Mianserin can be decreased when combined with Fluorouracil. Miconazole The metabolism of Fluorouracil can be decreased when combined with Miconazole. Mifepristone The serum concentration of Fluorouracil can be increased when it is combined with Mifepristone. Mirabegron The risk or severity of QTc prolongation can be increased when Mirabegron is combined with Fluorouracil. Mirtazapine The metabolism of Fluorouracil can be decreased when combined with Mirtazapine. Mitapivat The metabolism of Fluorouracil can be increased when combined with Mitapivat. Mitomycin The risk or severity of adverse effects can be increased when Mitomycin is combined with Fluorouracil. Mitoxantrone The risk or severity of adverse effects can be increased when Fluorouracil is combined with Mitoxantrone. Mizolastine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Mizolastine. Mobocertinib The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Mobocertinib. COVID-19 Vaccine The therapeutic efficacy of Moderna COVID-19 Vaccine can be decreased when used in combination with Fluorouracil. Modified vaccinia ankara The therapeutic efficacy of Modified vaccinia ankara can be decreased when used in combination with Fluorouracil. Moexipril The risk or severity of QTc prolongation can be increased when Moexipril is combined with Fluorouracil. Mometasone furoate The metabolism of Fluorouracil can be decreased when combined with Mometasone furoate. Monomethyl fumarate The risk or severity of adverse effects can be increased when Fluorouracil is combined with Monomethyl fumarate. Montelukast The metabolism of Fluorouracil can be decreased when combined with Montelukast. Moricizine The risk or severity of QTc prolongation can be increased when Moricizine is combined with Fluorouracil. Morphine The metabolism of Fluorouracil can be decreased when combined with Morphine. Mosunetuzumab The metabolism of Fluorouracil can be decreased when combined with Mosunetuzumab. Moxifloxacin The metabolism of Fluorouracil can be decreased when combined with Moxifloxacin. Mumps virus The therapeutic efficacy of Mumps virus strain B level jeryl lynn live antigen can be decreased when used in combination with Fluorouracil. Muromonab The risk or severity of adverse effects can be increased when Muromonab is combined with Fluorouracil. Mycophenolate mofetil The metabolism of Fluorouracil can be decreased when combined with Mycophenolate mofetil. Mycophenolic acid The risk or severity of adverse effects can be increased when Fluorouracil is combined with Mycophenolic acid. Nabilone The metabolism of Nabilone can be decreased when combined with Fluorouracil. Nabumetone The metabolism of Fluorouracil can be decreased when combined with Nabumetone. Nadroparin The risk or severity of bleeding can be increased when Nadroparin is combined with Fluorouracil. Nafcillin The metabolism of Fluorouracil can be increased when combined with Nafcillin. Nalidixic acid The metabolism of Fluorouracil can be decreased when combined with Nalidixic acid. Naproxen The metabolism of Fluorouracil can be decreased when combined with Naproxen. Natalizumab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Natalizumab. Nateglinide The metabolism of Nateglinide can be decreased when combined with Fluorouracil. Nelarabine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Nelarabine. Nelfinavir Nelfinavir may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Neomycin Neomycin can cause a decrease in the absorption of Fluorouracil resulting in a reduced serum concentration and potentially a decrease in efficacy. Netupitant The metabolism of Netupitant can be decreased when combined with Fluorouracil. Nevirapine The metabolism of Fluorouracil can be decreased when combined with Nevirapine. Nicardipine The metabolism of Fluorouracil can be decreased when combined with Nicardipine. Niclosamide The metabolism of Fluorouracil can be decreased when combined with Niclosamide. Nicotine The metabolism of Fluorouracil can be decreased when combined with Nicotine. Nifedipine The metabolism of Fluorouracil can be decreased when combined with Nifedipine. Nilotinib The risk or severity of adverse effects can be increased when Fluorouracil is combined with Nilotinib. Nilutamide The metabolism of Fluorouracil can be decreased when combined with Nilutamide. Nilvadipine The metabolism of Fluorouracil can be decreased when combined with Nilvadipine. Nimesulide The risk or severity of bleeding can be increased when Nimesulide is combined with Fluorouracil. Nimodipine The risk or severity of QTc prolongation can be increased when Nimodipine is combined with Fluorouracil. Nitrendipine The risk or severity of QTc prolongation can be increased when Nitrendipine is combined with Fluorouracil. Nitrofurantoin The therapeutic efficacy of Nitrofurantoin can be decreased when used in combination with Fluorouracil. Norfloxacin The metabolism of Fluorouracil can be decreased when combined with Norfloxacin. Norgestimate The metabolism of Norgestimate can be decreased when combined with Fluorouracil. Nortriptyline The risk or severity of QTc prolongation can be increased when Nortriptyline is combined with Fluorouracil. Novobiocin Novobiocin may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Nuvaxovid The therapeutic efficacy of Nuvaxovid can be decreased when used in combination with Fluorouracil. Obeticholic acid The risk or severity of adverse effects can be increased when Obeticholic acid is combined with Fluorouracil. Obinutuzumab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Obinutuzumab. Ocrelizumab Ocrelizumab may increase the immunosuppressive activities of Fluorouracil. Octreotide The risk or severity of QTc prolongation can be increased when Octreotide is combined with Fluorouracil. Ofatumumab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Ofatumumab. Ofloxacin The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Ofloxacin. Olanzapine The metabolism of Fluorouracil can be decreased when combined with Olanzapine. Olaparib The risk or severity of adverse effects can be increased when Fluorouracil is combined with Olaparib. Olodaterol The metabolism of Fluorouracil can be decreased when combined with Olodaterol. Ombitasvir The metabolism of Fluorouracil can be decreased when combined with Ombitasvir. Omeprazole The metabolism of Fluorouracil can be decreased when combined with Omeprazole. Ondansetron The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Ondansetron. Orphenadrine The metabolism of Fluorouracil can be decreased when combined with Orphenadrine. Osilodrostat The serum concentration of Fluorouracil can be increased when it is combined with Osilodrostat. Osimertinib The serum concentration of Fluorouracil can be decreased when it is combined with Osimertinib. Ospemifene The metabolism of Ospemifene can be decreased when combined with Fluorouracil. Oteseconazole The serum concentration of Fluorouracil can be increased when it is combined with Oteseconazole. Ouabain Ouabain may decrease the cardiotoxic activities of Fluorouracil. Oxaliplatin The risk or severity of adverse effects can be increased when Oxaliplatin is combined with Fluorouracil. Oxatomide The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Oxatomide. Oxetacaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Oxetacaine. Oxtriphylline The metabolism of Oxtriphylline can be decreased when combined with Fluorouracil. Oxybuprocaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Oxybuprocaine. Oxybutynin The metabolism of Fluorouracil can be decreased when combined with Oxybutynin. Oxytocin The risk or severity of QTc prolongation can be increased when Oxytocin is combined with Fluorouracil. Ozanimod The metabolism of Fluorouracil can be decreased when combined with Ozanimod. Paclitaxel The metabolism of Paclitaxel can be decreased when combined with Fluorouracil. Pacritinib The serum concentration of Fluorouracil can be increased when it is combined with Pacritinib. Palbociclib The risk or severity of adverse effects can be increased when Fluorouracil is combined with Palbociclib. Palifermin The therapeutic efficacy of Palifermin can be decreased when used in combination with Fluorouracil. Paliperidone The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Paliperidone. Panobinostat The risk or severity of adverse effects can be increased when Fluorouracil is combined with Panobinostat. Pantoprazole Pantoprazole may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Papaverine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Papaverine. Paramethadione The metabolism of Fluorouracil can be decreased when combined with Paramethadione. Parecoxib The metabolism of Parecoxib can be decreased when combined with Fluorouracil. Paritaprevir Paritaprevir may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Parnaparin The risk or severity of bleeding can be increased when Parnaparin is combined with Fluorouracil. Paroxetine The metabolism of Paroxetine can be decreased when combined with Fluorouracil. Pentoxifylline The metabolism of Pentoxifylline can be decreased when combined with Fluorouracil. Perampanel The metabolism of Perampanel can be decreased when combined with Fluorouracil. Perflutren The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Perflutren. Perhexiline The risk or severity of QTc prolongation can be increased when Perhexiline is combined with Fluorouracil. Perphenazine The metabolism of Perphenazine can be decreased when combined with Fluorouracil. Pertussis vaccine The therapeutic efficacy of Pertussis vaccine can be decreased when used in combination with Fluorouracil. Pertuzumab The risk or severity of cardiotoxicity can be increased when Fluorouracil is combined with Pertuzumab. Phenindione The risk or severity of bleeding can be increased when Fluorouracil is combined with Phenindione. Pheniramine The risk or severity of QTc prolongation can be increased when Pheniramine is combined with Fluorouracil. Phenobarbital The metabolism of Fluorouracil can be increased when combined with Phenobarbital. Phenol The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Phenol. Phenprocoumon The metabolism of Phenprocoumon can be decreased when combined with Fluorouracil. Phenylalanine The risk or severity of adverse effects can be increased when Phenylalanine is combined with Fluorouracil. Phenylbutazone The metabolism of Phenylbutazone can be decreased when combined with Fluorouracil. Phenylephrine The metabolism of Fluorouracil can be increased when combined with Phenylephrine. Phenytoin The serum concentration of Phenytoin can be increased when it is combined with Fluorouracil. Pibrentasvir Pibrentasvir may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Pilocarpine The metabolism of Fluorouracil can be decreased when combined with Pilocarpine. Pimecrolimus The risk or severity of adverse effects can be increased when Pimecrolimus is combined with Fluorouracil. Pimozide The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Pimozide. Pinaverium The risk or severity of QTc prolongation can be increased when Pinaverium is combined with Fluorouracil. Pioglitazone The metabolism of Fluorouracil can be decreased when combined with Pioglitazone. Piperaquine The metabolism of Piperaquine can be decreased when combined with Fluorouracil. Pirfenidone The risk or severity of adverse effects can be increased when Fluorouracil is combined with Pirfenidone. Piroxicam The metabolism of Fluorouracil can be decreased when combined with Piroxicam. Pitavastatin The metabolism of Fluorouracil can be decreased when combined with Pitavastatin. Pitolisant Fluorouracil may increase the QTc-prolonging activities of Pitolisant. Polythiazide The risk or severity of neutropenia and thrombocytopenia can be increased when Polythiazide is combined with Fluorouracil. Pomalidomide The risk or severity of adverse effects can be increased when Fluorouracil is combined with Pomalidomide. Ponatinib The metabolism of Ponatinib can be decreased when combined with Fluorouracil. Ponesimod The risk or severity of bradycardia can be increased when Ponesimod is combined with Fluorouracil. Posaconazole The risk or severity of QTc prolongation can be increased when Posaconazole is combined with Fluorouracil. Pralatrexate The risk or severity of adverse effects can be increased when Fluorouracil is combined with Pralatrexate. Pralsetinib The metabolism of Fluorouracil can be decreased when combined with Pralsetinib. Pramocaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Pramocaine. Prasugrel The metabolism of Prasugrel can be decreased when combined with Fluorouracil. Pravastatin Pravastatin may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Praziquantel The metabolism of Praziquantel can be decreased when combined with Fluorouracil. Prednisolone The risk or severity of adverse effects can be increased when Fluorouracil is combined with Prednisolone. Prednisolone The metabolism of Fluorouracil can be increased when combined with Prednisolone phosphate. Prednisone The metabolism of Fluorouracil can be increased when combined with Prednisone. Pregabalin The risk or severity of QTc prolongation can be increased when Pregabalin is combined with Fluorouracil. Prenylamine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Prenylamine. Prilocaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Prilocaine. Primaquine The metabolism of Fluorouracil can be increased when combined with Primaquine. Primidone The metabolism of Fluorouracil can be increased when combined with Primidone. Probenecid The metabolism of Fluorouracil can be increased when combined with Probenecid. Probucol The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Probucol. Procainamide The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Procainamide. Procaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Procaine. Procarbazine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Procarbazine. Prochlorperazine The risk or severity of QTc prolongation can be increased when Prochlorperazine is combined with Fluorouracil. Progesterone The metabolism of Fluorouracil can be increased when combined with Progesterone. Proguanil The metabolism of Proguanil can be decreased when combined with Fluorouracil. Promazine The metabolism of Fluorouracil can be decreased when combined with Promazine. Promethazine The risk or severity of QTc prolongation can be increased when Promethazine is combined with Fluorouracil. Propafenone The metabolism of Fluorouracil can be decreased when combined with Propafenone. Proparacaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Proparacaine. Propofol The metabolism of Fluorouracil can be decreased when combined with Propofol. Propoxycaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Propoxycaine. Propranolol The metabolism of Propranolol can be decreased when combined with Fluorouracil. Propylthiouracil The risk or severity of adverse effects can be increased when Fluorouracil is combined with Propylthiouracil. Protein C The risk or severity of bleeding can be increased when Protein C is combined with Fluorouracil. Protein S human The risk or severity of bleeding can be increased when Protein S human is combined with Fluorouracil. Protriptyline The risk or severity of QTc prolongation can be increased when Protriptyline is combined with Fluorouracil. Pyrimethamine The metabolism of Fluorouracil can be decreased when combined with Pyrimethamine. Quazepam The metabolism of Quazepam can be decreased when combined with Fluorouracil. Quetiapine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Quetiapine. Quinidine The metabolism of Fluorouracil can be decreased when combined with Quinidine. Quinine The metabolism of Fluorouracil can be decreased when combined with Quinine. Rabeprazole Rabeprazole may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Rabies immune The therapeutic efficacy of Rabies immune globulin, human can be decreased when used in combination with Fluorouracil. inactivated antigen The therapeutic efficacy of Rabies virus inactivated antigen, A can be decreased when used in combination with Fluorouracil. Rabies virus The therapeutic efficacy of Rabies virus inactivated antigen, B can be decreased when used in combination with Fluorouracil. Raloxifene The metabolism of Fluorouracil can be decreased when combined with Raloxifene. Raltitrexed The risk or severity of adverse effects can be increased when Raltitrexed is combined with Fluorouracil. Ramelteon The metabolism of Ramelteon can be decreased when combined with Fluorouracil. Ranitidine The metabolism of Ranitidine can be decreased when combined with Fluorouracil. Ranolazine The risk or severity of QTc prolongation can be increased when Ranolazine is combined with Fluorouracil. Rasagiline The metabolism of Rasagiline can be decreased when combined with Fluorouracil. Ravulizumab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Ravulizumab. Regorafenib Regorafenib may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Relugolix The risk or severity of QTc prolongation can be increased when Relugolix is combined with Fluorouracil. Repaglinide The metabolism of Fluorouracil can be decreased when combined with Repaglinide. Ribociclib The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Ribociclib. Rifabutin The metabolism of Fluorouracil can be increased when combined with Rifabutin. Rifampicin The metabolism of Fluorouracil can be increased when combined with Rifampicin. Rifamycin The metabolism of Fluorouracil can be decreased when combined with Rifamycin. Rifapentine The metabolism of Fluorouracil can be increased when combined with Rifapentine. Rilonacept The metabolism of Fluorouracil can be increased when combined with Rilonacept. Rilpivirine The metabolism of Fluorouracil can be decreased when combined with Rilpivirine. Riluzole The metabolism of Riluzole can be decreased when combined with Fluorouracil. Riociguat The metabolism of Fluorouracil can be decreased when combined with Riociguat. Ripretinib Ripretinib may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Risankizumab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Risankizumab. Risperidone The risk or severity of QTc prolongation can be increased when Risperidone is combined with Fluorouracil. Ritonavir The metabolism of Fluorouracil can be decreased when combined with Ritonavir. Rituximab The risk or severity of adverse effects can be increased when Rituximab is combined with Fluorouracil. Rivaroxaban The risk or severity of bleeding can be increased when Rivaroxaban is combined with Fluorouracil. Rofecoxib The metabolism of Fluorouracil can be decreased when combined with Rofecoxib. Roflumilast Roflumilast may increase the immunosuppressive activities of Fluorouracil. Rolapitant Rolapitant may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Romidepsin The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Romidepsin. Ropeginterferon The risk or severity of adverse effects can be increased when Fluorouracil is combined with Ropeginterferon alfa-2b. Ropivacaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Ropivacaine. Rosiglitazone The metabolism of Fluorouracil can be decreased when combined with Rosiglitazone. Rosoxacin The metabolism of Fluorouracil can be decreased when combined with Rosoxacin. Rosuvastatin The metabolism of Rosuvastatin can be decreased when combined with Fluorouracil. Rotavirus vaccine The therapeutic efficacy of Rotavirus vaccine can be decreased when used in combination with Fluorouracil. Roxadustat The serum concentration of Fluorouracil can be increased when it is combined with Roxadustat. Roxithromycin The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Roxithromycin. Rubella virus vaccine The risk or severity of infection can be increased when Rubella virus vaccine is combined with Fluorouracil. Rucaparib The metabolism of Fluorouracil can be decreased when combined with Rucaparib. Rupatadine The metabolism of Rupatadine can be decreased when combined with Fluorouracil. Ruxolitinib The metabolism of Ruxolitinib can be decreased when combined with Fluorouracil. Safinamide Safinamide may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Salbutamol The risk or severity of QTc prolongation can be increased when Salbutamol is combined with Fluorouracil. Salicylic acid The metabolism of Salicylic acid can be decreased when combined with Fluorouracil. Salmeterol The metabolism of Fluorouracil can be decreased when combined with Salmeterol. Saquinavir The metabolism of Fluorouracil can be decreased when combined with Saquinavir. Sarilumab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Sarilumab. Satralizumab The serum concentration of Fluorouracil can be decreased when it is combined with Satralizumab. Secobarbital The metabolism of Fluorouracil can be increased when combined with Secobarbital. Secukinumab The metabolism of Fluorouracil can be increased when combined with Secukinumab. Selegiline The metabolism of Fluorouracil can be decreased when combined with Selegiline. Selexipag The metabolism of Fluorouracil can be decreased when combined with Selexipag. Selpercatinib The serum concentration of Fluorouracil can be increased when it is combined with Selpercatinib. Selumetinib The metabolism of Fluorouracil can be decreased when combined with Selumetinib. Sertraline The metabolism of Sertraline can be decreased when combined with Fluorouracil. Sevoflurane The metabolism of Fluorouracil can be decreased when combined with Sevoflurane. Sildenafil The metabolism of Sildenafil can be decreased when combined with Fluorouracil. Siltuximab The metabolism of Fluorouracil can be increased when combined with Siltuximab. Simeprevir The metabolism of Fluorouracil can be decreased when combined with Simeprevir. Simvastatin The metabolism of Fluorouracil can be decreased when combined with Simvastatin. Siponimod The metabolism of Siponimod can be decreased when combined with Fluorouracil. Sipuleucel-T The therapeutic efficacy of Sipuleucel-T can be decreased when used in combination with Fluorouracil. Sirolimus The risk or severity of adverse effects can be increased when Fluorouracil is combined with Sirolimus. Sitagliptin The metabolism of Fluorouracil can be decreased when combined with Sitagliptin. Sitaxentan The metabolism of Sitaxentan can be decreased when combined with Fluorouracil. Smallpox The therapeutic efficacy of Smallpox (Vaccinia) Vaccine, Live can be decreased when used in combination with Fluorouracil. Sodium citrate The risk or severity of bleeding can be increased when Sodium citrate is combined with Fluorouracil. Solifenacin The risk or severity of QTc prolongation can be increased when Solifenacin is combined with Fluorouracil. Somapacitan The metabolism of Fluorouracil can be increased when combined with Somapacitan. Somatotropin The metabolism of Fluorouracil can be increased when combined with Somatotropin. Somatrem The metabolism of Fluorouracil can be increased when combined with Somatrem. Somatrogon The metabolism of Fluorouracil can be increased when combined with Somatrogon. Sorafenib The risk or severity of QTc prolongation can be increased when Sorafenib is combined with Fluorouracil. Sotagliflozin Sotagliflozin may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Sotalol The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Sotalol. Sparfloxacin The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Sparfloxacin. Spesolimab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Spesolimab. Spironolactone The metabolism of Fluorouracil can be decreased when combined with Spironolactone. Stiripentol The metabolism of Fluorouracil can be decreased when combined with Stiripentol. Streptokinase The risk or severity of bleeding can be increased when Streptokinase is combined with Fluorouracil. Streptozocin The risk or severity of adverse effects can be increased when Streptozocin is combined with Fluorouracil. Sulfadiazine The metabolism of Fluorouracil can be decreased when combined with Sulfadiazine. Sulfamethoxazole The risk or severity of myelosuppression can be increased when Sulfamethoxazole is combined with Fluorouracil. Sulfaphenazole The metabolism of Fluorouracil can be decreased when combined with Sulfaphenazole. Sulfasalazine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Sulfasalazine. Sulfinpyrazone The risk or severity of bleeding can be increased when Sulfinpyrazone is combined with Fluorouracil. Sulfisoxazole The risk or severity of QTc prolongation can be increased when Sulfisoxazole is combined with Fluorouracil. Sulodexide The risk or severity of bleeding can be increased when Sulodexide is combined with Fluorouracil. Sulpiride The risk or severity of QTc prolongation can be increased when Sulpiride is combined with Fluorouracil. Sultopride The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Sultopride. Sunitinib The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Sunitinib. Tacrine The metabolism of Fluorouracil can be decreased when combined with Tacrine. Tacrolimus Tacrolimus may increase the immunosuppressive activities of Fluorouracil. Tafamidis The serum concentration of Fluorouracil can be increased when it is combined with Tafamidis. Tamoxifen The metabolism of Fluorouracil can be decreased when combined with Tamoxifen. Tasimelteon The metabolism of Tasimelteon can be decreased when combined with Fluorouracil. Taurocholic acid Taurocholic acid may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Tazarotene The metabolism of Fluorouracil can be decreased when combined with Tazarotene. Tecovirimat The metabolism of Fluorouracil can be increased when combined with Tecovirimat. Tedizolid phosphate The risk or severity of myelosuppression can be increased when Fluorouracil is combined with Tedizolid phosphate. Tegafur The metabolism of Tegafur can be decreased when combined with Fluorouracil. Tegafur-uracil The metabolism of Fluorouracil can be decreased when combined with Tegafur-uracil. Tegaserod The metabolism of Fluorouracil can be decreased when combined with Tegaserod. Telavancin The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Telavancin. Telithromycin The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Telithromycin. Telmisartan Telmisartan may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Temozolomide The risk or severity of adverse effects can be increased when Fluorouracil is combined with Temozolomide. Temsirolimus The risk or severity of adverse effects can be increased when Fluorouracil is combined with Temsirolimus. Tenoxicam The metabolism of Tenoxicam can be decreased when combined with Fluorouracil. Tepotinib Tepotinib may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Teprotumumab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Teprotumumab. Terbinafine The metabolism of Fluorouracil can be decreased when combined with Terbinafine. Terbutaline The risk or severity of QTc prolongation can be increased when Terbutaline is combined with Fluorouracil. Terfenadine The metabolism of Fluorouracil can be decreased when combined with Terfenadine. Teriflunomide The serum concentration of Fluorouracil can be decreased when it is combined with Teriflunomide. Terlipressin The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Terlipressin. Testosterone The metabolism of Testosterone can be decreased when combined with Fluorouracil. Testosterone The metabolism of Fluorouracil can be decreased when combined with Testosterone cypionate. Testosterone The metabolism of Fluorouracil can be decreased when combined with Testosterone enanthate. Tetrabenazine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Tetrabenazine. Tetracaine The risk or severity of methemoglobinemia can be increased when Fluorouracil is combined with Tetracaine. Thalidomide The risk or severity of adverse effects can be increased when Fluorouracil is combined with Thalidomide. Theophylline The metabolism of Fluorouracil can be decreased when combined with Theophylline. Thiabendazole The metabolism of Fluorouracil can be decreased when combined with Thiabendazole. Thiamylal The metabolism of Thiamylal can be decreased when combined with Fluorouracil. Thioridazine The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Thioridazine. Thiotepa The risk or severity of adverse effects can be increased when Fluorouracil is combined with Thiotepa. Thiothixene The metabolism of Thiothixene can be decreased when combined with Fluorouracil. Ticagrelor The risk or severity of bleeding can be increased when Ticagrelor is combined with Fluorouracil. Tick-borne The therapeutic efficacy of Tick-borne encephalitis vaccine (whole virus, inactivated) can be decreased when used in combination with Fluorouracil. Ticlopidine The metabolism of Fluorouracil can be decreased when combined with Ticlopidine. Timolol The risk or severity of QTc prolongation can be increased when Timolol is combined with Fluorouracil. Tinzaparin The risk or severity of bleeding can be increased when Tinzaparin is combined with Fluorouracil. Tioguanine The risk or severity of adverse effects can be increased when Tioguanine is combined with Fluorouracil. Tirofiban The risk or severity of bleeding can be increased when Tirofiban is combined with Fluorouracil. Tivozanib Tivozanib may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Tixocortol The risk or severity of adverse effects can be increased when Fluorouracil is combined with Tixocortol. Tizanidine The metabolism of Tizanidine can be decreased when combined with Fluorouracil. Tocainide The metabolism of Fluorouracil can be decreased when combined with Tocainide. Tocilizumab The metabolism of Fluorouracil can be increased when combined with Tocilizumab. Tofacitinib Fluorouracil may increase the immunosuppressive activities of Tofacitinib. Tolazamide The metabolism of Tolazamide can be decreased when combined with Fluorouracil. Tolbutamide The metabolism of Fluorouracil can be decreased when combined with Tolbutamide. Tolterodine The metabolism of Tolterodine can be decreased when combined with Fluorouracil. Topotecan The risk or severity of adverse effects can be increased when Fluorouracil is combined with Topotecan. Torasemide The metabolism of Fluorouracil can be decreased when combined with Torasemide. Toremifene The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Toremifene. Tositumomab The risk or severity of adverse effects can be increased when Tositumomab is combined with Fluorouracil. Trabectedin The metabolism of Trabectedin can be decreased when combined with Fluorouracil. Trametinib The metabolism of Fluorouracil can be decreased when combined with Trametinib. Tranylcypromine The metabolism of Fluorouracil can be decreased when combined with Tranylcypromine. Trastuzumab Trastuzumab may increase the neutropenic activities of Fluorouracil. Trastuzumab emtansine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Trastuzumab emtansine. Trazodone The risk or severity of QTc prolongation can be increased when Trazodone is combined with Fluorouracil. Treprostinil The metabolism of Fluorouracil can be decreased when combined with Treprostinil. Tretinoin The metabolism of Fluorouracil can be decreased when combined with Tretinoin. Triamcinolone The risk or severity of adverse effects can be increased when Fluorouracil is combined with Triamcinolone. Triamterene The metabolism of Fluorouracil can be decreased when combined with Triamterene. Trichlormethiazide The risk or severity of neutropenia and thrombocytopenia can be increased when Trichlormethiazide is combined with Fluorouracil. Triclabendazole The metabolism of Fluorouracil can be decreased when combined with Triclabendazole. Trifluoperazine The metabolism of Trifluoperazine can be decreased when combined with Fluorouracil. Trifluridine The risk or severity of adverse effects can be increased when Trifluridine is combined with Fluorouracil. Triflusal The risk or severity of bleeding can be increased when Triflusal is combined with Fluorouracil. Trilaciclib The metabolism of Fluorouracil can be increased when combined with Trilaciclib. Trilostane The risk or severity of adverse effects can be increased when Fluorouracil is combined with Trilostane. Trimebutine The risk or severity of QTc prolongation can be increased when Trimebutine is combined with Fluorouracil. Trimethadione The metabolism of Fluorouracil can be decreased when combined with Trimethadione. Trimethoprim The metabolism of Fluorouracil can be decreased when combined with Trimethoprim. Trimipramine The metabolism of Trimipramine can be decreased when combined with Fluorouracil. Triprolidine The risk or severity of QTc prolongation can be increased when Triprolidine is combined with Fluorouracil. Triptorelin The risk or severity of QTc prolongation can be increased when Triptorelin is combined with Fluorouracil. Troglitazone The metabolism of Fluorouracil can be decreased when combined with Troglitazone. Trovafloxacin The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Trovafloxacin. Tucatinib The metabolism of Fluorouracil can be decreased when combined with Tucatinib. Typhoid vaccine The therapeutic efficacy of Typhoid vaccine can be decreased when used in combination with Fluorouracil. Typhoid Vaccine Live The risk or severity of infection can be increased when Typhoid Vaccine Live is combined with Fluorouracil. Typhoid Vi The therapeutic efficacy of Typhoid Vi polysaccharide vaccine can be decreased when used in combination with Fluorouracil. Upadacitinib The risk or severity of adverse effects can be increased when Fluorouracil is combined with Upadacitinib. Urokinase The risk or severity of bleeding can be increased when Urokinase is combined with Fluorouracil. Valdecoxib The metabolism of Valdecoxib can be decreased when combined with Fluorouracil. Valproic acid The metabolism of Fluorouracil can be decreased when combined with Valproic acid. Valsartan The metabolism of Valsartan can be decreased when combined with Fluorouracil. Vandetanib The risk or severity of QTc prolongation can be increased when Fluorouracil is combined with Vandetanib. Vardenafil The risk or severity of QTc prolongation can be increased when Vardenafil is combined with Fluorouracil. Varicella zoster vaccine The risk or severity of infection can be increased when Varicella zoster vaccine (live/attenuated) is combined with Fluorouracil. Varicella zoster vaccine The therapeutic efficacy of Varicella zoster vaccine (recombinant) can be decreased when used in combination with Fluorouracil. Vedolizumab The risk or severity of adverse effects can be increased when Fluorouracil is combined with Vedolizumab. Velpatasvir The metabolism of Fluorouracil can be decreased when combined with Velpatasvir. Vemurafenib The serum concentration of Fluorouracil can be increased when it is combined with Vemurafenib. Venetoclax Venetoclax may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Venlafaxine Venlafaxine may increase the excretion rate of Fluorouracil which could result in a lower serum level and potentially a reduction in efficacy. Verapamil The metabolism of Fluorouracil can be decreased when combined with Verapamil. Vernakalant The risk or severity of QTc prolongation can be increased when Vernakalant is combined with Fluorouracil. Vibrio cholerae The therapeutic efficacy of Vibrio cholerae CVD 103-HgR strain live antigen can be decreased when used in combination with Fluorouracil. Vilanterol The risk or severity of adverse effects can be increased when Fluorouracil is combined with Vilanterol. Viloxazine The metabolism of Fluorouracil can be decreased when combined with Viloxazine. Vinblastine The risk or severity of adverse effects can be increased when Fluorouracil is combined with Vinblastine. Vincristine The risk or severity of adverse effects can be increased when Vincristine is combined with Fluorouracil. Vindesine The risk or severity of adverse effects can be increased when Vindesine is combined with Fluorouracil. Vinorelbine The risk or severity of adverse effects can be increased when Vinorelbine is combined with Fluorouracil. Vismodegib Vismodegib may decrease the excretion rate of Fluorouracil which could result in a higher serum level. Voclosporin The risk or severity of adverse effects can be increased when Fluorouracil is combined with Voclosporin. Vorapaxar The risk or severity of bleeding can be increased when Vorapaxar is combined with Fluorouracil. Voriconazole The metabolism of Voriconazole can be decreased when combined with Fluorouracil. Vorinostat The risk or severity of adverse effects can be increased when Fluorouracil is combined with Vorinostat. Vortioxetine The metabolism of Fluorouracil can be decreased when combined with Vortioxetine. Pregnancy and lactation AU TGA pregnancy category: D US FDA pregnancy category: Not assigned. Pregnancy This drug can harm a developing fetus when administered to a pregnant woman. No adequate and well-controlled studies have been conducted in pregnant women with either topical or parenteral forms. One birth defect (ventricular septal defect) and cases of miscarriage have been reported when this drug was applied to mucous membrane areas. Multiple birth defects have been reported in the fetus of a patient treated with the IV formulation. Lactation Most sources consider breastfeeding to be contraindicated during maternal antineoplastic drug therapy. It might be possible to breastfeed safely during intermittent therapy with an appropriate period of breastfeeding abstinence, but the duration of abstinence is not clear. How should this medicine be used?

Fluorouracil comes as a solution and a cream to apply to the skin. It is usually applied to the affected areas twice a day. To help you remember to use fluorouracil, apply it around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Use fluorouracil exactly as directed. Do not apply more or less of it or apply it more often than…

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  5. Imidazole – Uses, Dosage, Side Effects, Interactions

    Imidazole is an imidazole tautomer which has the migrating hydrogen at position 1. It is a conjugate base of an imidazolium cation. It is a conjugate acid of an imidazolide. It is...

    October 20, 2023 • Drugs (A - Z)
  6. Carbimazole

    Carbimazole is a member of the class of imidazoles that is methimazole in which the nitrogen-bearing hydrogen is converted into its methoxycarbonyl derivative. A prodrug for methimazole, carbimazole is...

    October 20, 2023 • Drugs (A - Z)
  7. Methylthiouracil – Uses, Dosage, Side Effects, Interactions

    A thiourea antithyroid agent that inhibits the synthesis of thyroid? hormone. It is used in the treatment of hyperthyroidism?. Methylthiouracil is an organosulfur compound that is used in...

    October 20, 2023 • Drugs (A - Z)
  8. Propylthiouracil – Uses, Dosage, Side Effects, Interactions

    Propylthiouracil is a Thyroid? Hormone Synthesis Inhibitor. The mechanism of action of propylthiouracil is as a Thyroid Hormone Synthesis Inhibitor. 6-propyl-2-thiouracil is a pyrimidine-thione consisting of uracil in which the...

    October 20, 2023 • Drugs (A - Z)
  9. Methimazole

    Methimazole ( Metirox 5 and 10 mg) is a member of the class of imidazoles that it imidazole-2-thione in which a methyl group replaces the hydrogen that is attached to...

    October 20, 2023 • Drugs (A - Z)
  10. Mirogabalin – Uses, Dosage, Side Effects, Interactions

    Mirogabalin has been used in trials studying the treatment of Post-herpetic Neuralgia, Pain? Associated With Fibromyalgia, and Diabetic peripheral neuropathic pain. Mirogabalin is a medication designed...

    August 12, 2023 • Drugs (A - Z)