Hydroxychloroquine, Uses, Dosage, Side Effects, Interactions, Pregnancy

Last updated: February 7, 2026Reviewed date: February 7, 2026Reading time: 6 min read
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Hydroxychloroquine is a 4-aminoquinoline with immunosuppressive, antiautophagy, and antimalarial activities. Although the precise mechanism of action is unknown, hydroxychloroquine may suppress immune function by interfering with the processing and presentation of antigens and the production of cytokines. As a lysosomotropic agent, hydroxychloroquine raises intralysosomal pH, impairing autophagic protein degradation; hydroxychloroquine-mediated accumulation of ineffective...

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

এই তথ্য শিক্ষা ও সচেতনতার জন্য। এটি ডাক্তারি পরীক্ষা, রোগ নির্ণয় বা প্রেসক্রিপশনের বিকল্প নয়।

Article Summary

Hydroxychloroquine is a 4-aminoquinoline with immunosuppressive, antiautophagy, and antimalarial activities. Although the precise mechanism of action is unknown, hydroxychloroquine may suppress immune function by interfering with the processing and presentation of antigens and the production of cytokines. As a lysosomotropic agent, hydroxychloroquine raises intralysosomal pH, impairing autophagic protein degradation; hydroxychloroquine-mediated accumulation of ineffective autophagosomes may result in cell death in tumor cells reliant on autophagy for survival. In addition, this agent is highly...

Key Takeaways

  • This article explains Mechanism of Action of Hydroxychloroquine in simple medical language.
  • This article explains Indications of Hydroxychloroquine in simple medical language.
  • This article explains Contra-Indications of Hydroxychloroquine in simple medical language.
  • This article explains Dosage of Hydroxychloroquine in simple medical language.
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Definition

Hydroxychloroquine is a 4-aminoquinoline with immunosuppressive, antiautophagy, and antimalarial activities. Although the precise mechanism of action is unknown, hydroxychloroquine may suppress immune function by interfering with the processing and presentation of antigens and the production of cytokines. As a lysosomotropic agent, hydroxychloroquine raises intralysosomal pH, impairing autophagic protein degradation; hydroxychloroquine-mediated accumulation of ineffective autophagosomes may result in cell death in tumor cells reliant on autophagy for survival. In addition, this agent is highly active against the erythrocytic forms of P. vivax and malaria and most strains of P. falciparum but not the gametocytes of P. falciparum.

Hydroxychloroquine is a derivative of chloroquine that has both antimalarial and infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation, pain, or swelling. সহজ বাংলা: প্রদাহ/ফোলা/ব্যথা কমায়।" data-rx-term="anti-inflammatory" data-rx-definition="Anti-inflammatory means reducing inflammation, pain, or swelling. সহজ বাংলা: প্রদাহ/ফোলা/ব্যথা কমায়।">anti-inflammatory activities and is now most often used as an antirheumatologic agent in systemic lupus erythematosus and stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।" data-rx-term="arthritis" data-rx-definition="Arthritis means joint inflammation causing pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।">arthritis: Rheumatoid arthritis is an autoimmune joint disease causing inflammation, pain, and swelling. সহজ বাংলা: রোগপ্রতিরোধ ব্যবস্থার ভুল আক্রমণে জয়েন্টের প্রদাহ।" data-rx-term="rheumatoid arthritis" data-rx-definition="Rheumatoid arthritis is an autoimmune joint disease causing inflammation, pain, and swelling. সহজ বাংলা: রোগপ্রতিরোধ ব্যবস্থার ভুল আক্রমণে জয়েন্টের প্রদাহ।">rheumatoid arthritis. Hydroxychloroquine therapy has not been associated with liver function abnormalities and is an extremely rare cause of clinically apparent acute liver injury.

Hydroxychloroquine (HCQ) is a lupus erythematosus (chronic discoid or systemic) and acute or chronic pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।" data-rx-term="arthritis" data-rx-definition="Arthritis means joint inflammation causing pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।">arthritis: Rheumatoid arthritis is an autoimmune joint disease causing infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation, pain, and swelling. সহজ বাংলা: রোগপ্রতিরোধ ব্যবস্থার ভুল আক্রমণে জয়েন্টের প্রদাহ।" data-rx-term="rheumatoid arthritis" data-rx-definition="Rheumatoid arthritis is an autoimmune joint disease causing inflammation, pain, and swelling. সহজ বাংলা: রোগপ্রতিরোধ ব্যবস্থার ভুল আক্রমণে জয়েন্টের প্রদাহ।">rheumatoid arthritis drug is a medication used for the prevention and treatment of certain types of malaria.

Mechanism of Action of Hydroxychloroquine

Although the exact mechanism of action is unknown, it may be based on the ability of hydroxychloroquine to bind to and alter DNA. Hydroxychloroquine has also has been found to be taken up into the acidic food vacuoles of the parasite in the erythrocyte. This increases the pH of the acid vesicles, interfering with vesicle functions and possibly inhibiting phospholipid metabolism. In suppressive treatment, hydroxychloroquine inhibits the erythrocytic stage of development of plasmodia. In acute attacks of malaria, it interrupts erythrocytic schizogony of the parasite. Its ability to concentrate in parasitized erythrocytes may account for their selective toxicity against the erythrocytic stages of plasmodial infection. As an antirheumatic, hydroxychloroquine is thought to act as a mild immunosuppressant, inhibiting the production of rheumatoid factor and acute phase reactants. It also accumulates in white blood cells, stabilizing lysosomal membranes and inhibiting the activity of many enzymes, including collagenase and the proteases that cause cartilage breakdown.

Indications of Hydroxychloroquine

  • Rheumatoid Arthritis
  • Juvenile idiopathic arthritis (in children)
  • Discoid and systemic lupus erythematosus (a disease of the skin or the internal organs)
  • Skin problems which are sensitive to sunlight
  • Lyme Disease, pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।" data-rx-term="arthritis" data-rx-definition="Arthritis means joint inflammation causing pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।">Arthritis
  • Dermatomyositis
  • Malaria
  • Systemic Lupus Erythematosus
  • Malaria Prevention
  • Sjogren’s Syndrome
  • Undifferentiated Connective Tissue Disease
  • Discoid Lupus Erythematosus
  • Malaria caused by Plasmodium malaria
  • Malaria caused by Plasmodium ovale
  • Malaria caused by plasmodium vivax
  • Porphyria Cutanea Tarda
  • Q Fever
  • Sjögren’s Syndrome
  • Systemic Lupus Erythematosus

Contra-Indications of Hydroxychloroquine

  • Hyper sense. to drug class common.
  • Retinal or visual field changes
  • Concurrent hepatotoxic agent use
  • Hepatic impairment
  • Alcoholism
  • Pediatric pts
  • Psoriasis
  • Porphyria
  • Electrolyte abnormalities
  • Congenital long QT syndrome
  • QT prolongation
  • QT prolongation family hx
  • Ventricular arrhythmias
  • Bradycardia

Dosage of Hydroxychloroquine

Strength: 200 mg, 400 mg

Lupus Erythematosus

  • Typical starting dosage: 400 mg taken once or twice per day.
  • Typical maintenance dosage: 200–400 mg per day.

Rheumatoid Arthritis

  • Initial dose: 400 to 600 mg (310 to 465 mg base) orally once a day to optimum response (usually 4 to 12 weeks)
  • Maintenance dose: 200 to 400 mg (155 to 310 mg base) orally once a day
  • Dose adjustment: The dose may need to be reduced temporarily if adverse side effects occur; after 5 to 10 days the dose may gradually be increased to the optimum response level.
  • Maintenance dose: 200 to 400 mg (155 mg to 310 mg base) orally daily

Arthritis

  • Typical starting dosage: 400–600 mg per day for 5–10 days.
  • Dosage increases: Your doctor may increase your dosage based on how well the medication is working for you.
  • Maintenance dosage: 4–12 weeks after your starting dose, your doctor may lower your dosage to 200–400 mg per day.

Malaria

Adult dosage (ages 18 years and older)

  • The typical starting dose is 800 mg. This is followed by 400 mg three times: 6 hours after the first dose, 24 hours after the first dose, and 48 hours after the first dose.

Side Effects of Hydroxychloroquine

The more common side effects 

Common

Rare

Drug Interactions of Hydroxychloroquine

Hydroxychloroquine may interact with following drugs, supplements, & may change the efficacy of drugs

 Hydroxychloroquine additional drug interaction

  • Some antibiotics used for infections (such as gentamicin, neomycin or tobramycin)
  • Cimetidine – used for stomach ulcers
  • Neostigmine and pyridostigmine – used for muscle weakness (myasthenia gravis)
  • Medicines that may affect the kidneys or liver
  • Medicines that affect the skin or the eyes
  • Halofantrine, mefloquine – used for malaria
  • Amiodarone – used for heart problems
  • Moxifloxacin – used to treat infections
  • Medicines used for epilepsy

Pregnancy & Lactation

FDA  Pregnancy Category D

Pregnancy

Use of chloroquine and other 4-aminoquinolines in high doses and for prolonged durations has been associated with neurological disturbances and interference with hearing, balance, and vision in the fetus. There are no controlled data in human pregnancy. Drugs which have caused, are suspected to have caused or may be expected to cause, an increased incidence of human fetal malformations or irreversible damage.

Lactation

Infants exposed to hydroxychloroquine during breastfeeding receive only small amounts of the drug in breastmilk. In a small number of infants up to at least 1 year of age, careful follow-up found no adverse effects on growth, vision or hearing. International experts indicate that hydroxychloroquine is acceptable during breastfeeding.

References

Hydroxychloroquine, Uses, Dosage, Side Effects, Interactions, Pregnancy

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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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Patient health record and symptom diary

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: Hydroxychloroquine, Uses, Dosage, Side Effects, Interactions, Pregnancy

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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Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area from the RX Article Professional Blocks panel.

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