Imipenem – Uses, Dosage, Side Effects, Interactions

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 6 min read
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Imipenem is a semisynthetic thienamycin that has a wide spectrum of antibacterial activity against gram-negative and gram-positive aerobic and anaerobic bacteria, including many multiresistant strains. It is stable to many beta-lactamases. Similar compounds include meropenem, known for having greater activity against Gram-negative bacteria, and the newer...

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

Imipenem is a semisynthetic thienamycin that has a wide spectrum of antibacterial activity against gram-negative and gram-positive aerobic and anaerobic bacteria, including many multiresistant strains. It is stable to many beta-lactamases. Similar compounds include meropenem, known for having greater activity against Gram-negative bacteria, and the newer ertapenem which exhibits a longer half-life due to increased binding to plasma proteins.[rx]Imipenem is commonly used in combination with cilastatin and is...

Key Takeaways

  • This article explains Mechanism of action in simple medical language.
  • This article explains Indications of Imipenem in simple medical language.
  • This article explains Contraindications of Imipenem in simple medical language.
  • This article explains Dosage of Imipenem in simple medical language.
Educational health guideWritten for patient understanding and clinical awareness.
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Emergency safety firstUrgent warning signs are highlighted below.

Seek urgent medical care if you notice

These warning signs are general safety guidance. Local emergency numbers and clinical judgment should always come first.

  • Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
  • New weakness, severe pain, high fever, or symptoms after a serious injury.
  • Any symptom that feels urgent, unusual, or unsafe for the patient.
1

Emergency now

Use emergency care for severe, sudden, rapidly worsening, or life-threatening symptoms.

2

See a doctor

Book a professional medical evaluation if symptoms persist, worsen, recur often, affect daily activities, or occur in a high-risk patient.

3

Learn safely

Use this article to understand possible causes, tests, treatment options, prevention, and questions to ask your clinician.

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Definition

Imipenem is a semisynthetic thienamycin that has a wide spectrum of antibacterial activity against gram-negative and gram-positive aerobic and anaerobic bacteria, including many multiresistant strains. It is stable to many beta-lactamases. Similar compounds include meropenem, known for having greater activity against Gram-negative bacteria, and the newer ertapenem which exhibits a longer half-life due to increased binding to plasma proteins.[rx]Imipenem is commonly used in combination with cilastatin and is now available in a triple-drug product with cilastatin and sulbactam which was recently approved by the FDA. Imipenem was first approved by the FDA in November 1985 as the combination product Primaxin marketed by Merck & Co.[rx]

Imipenem and cilastatin injection is used to treat certain serious infections that are caused by bacteria, including endocarditis (infection of the heart lining and valves) and respiratory tract (including pneumonia), urinary tract, abdominal (stomach area), gynecological, blood, skin, bone, and joint infections. Imipenem is in a class of medications called carbapenem antibiotics. It works by killing bacteria. Cilastatin is in a class of medications called dehydropeptidase inhibitors. It works by helping imipenem stay active in your body for a longer period of time.

Mechanism of action

Imipenem acts as an antimicrobial through the inhibition of cell wall synthesis of various gram-positive and gram-negative bacteria.[rx] This inhibition of cell wall synthesis in gram-negative bateria is attained by binding to penicillin-binding proteins (PBPs). In E. coli and selected strains of P. aeruginosa, imipenem has shown to have the highest affinity to PBP-2, PBP-1a, and PBP-1b.[rx] This inhibition of PBPs prevents the bacterial cell from adding to the peptidoglycan polymer which forms the bacterial cell wall eventually leading to cell death.[rx]

Imipenem is a beta-lactam bacterial infections. সহজ বাংলা: ব্যাকটেরিয়ার সংক্রমণের ওষুধ।" data-rx-term="antibiotic" data-rx-definition="An antibiotic is a medicine used to treat bacterial infections. সহজ বাংলা: ব্যাকটেরিয়ার সংক্রমণের ওষুধ।">antibiotic belongings to the subgroup of carbapenems.[rx] Imipenem is active against aerobic and anaerobic Gram-positive as well as Gram-negative bacteria including Pseudomonas aeruginosa and Enterococcus. It exerts a bactericidal effect by disrupting cell wall synthesis.

Indications of Imipenem

The spectrum of bacterial susceptibility and resistance

  • Acinetobacter anitratus, Acinetobacter calcoaceticus, Actinomyces odontolyticus, Aeromonas hydrophila, Bacteroides distasonis, Bacteroides uniformis, and Clostridium perfringens are generally susceptible to imipenem, while Acinetobacter baumannii, some Acinetobacter spp., Bacteroides fragilis, and Enterococcus faecalis have developed resistance to imipenem to varying degrees. Not many species are resistant to imipenem except Pseudomonas aeruginosa (Oman) and Stenotrophomonas maltophilia.[rx]

Coadministration with cilastatin

  • Imipenem is rapidly degraded by the renal enzyme dehydropeptidase 1 when administered alone, and is almost always coadministered with cilastatin to prevent this inactivation.[rx]
  • Imipenem is indicated, in combination with cilastatin with or without sulbactam, for the treatment of bacterial infections including respiratory, skin, bone, gynecologic, urinary tract, and intra-abdominal as well as septicemia and endocarditis.[rx]
  • Bloodstream Infections
  • Bone and Joint Infections
  • Complicated Intra-Abdominal Infections
  • Complicated Urinary Infection
  • Complicated Urinary Tract Infection
  • Endocarditis caused by staphylococcus aureus
  • Gynecological infection
  • Intra-Abdominal Infections
  • Lower respiratory tract infection bacterial
  • Pyelonephritis
  • Skin and Subcutaneous Tissue Bacterial Infections
  • Uncomplicated Urinary Tract Infections

Contraindications of Imipenem

  • Children less than 30 kg with renal impairment, children with CNS infections (increased seizure risk), known hypersensitivity to local anesthetics of the amide-type, and in patients with severe shock or heart block
  • History of seizures,
  • Concomitant ganciclovir; risk for generalized seizures,
  • Hypersensitivity to penicillins,
  • cephalosporins, and other beta-lactams

Dosage of Imipenem

Strengths: 500mg, 750mg

Intramuscular

  • 500mg imipenem and 500mg cilastatin power mixture for intramuscular injection
  • 750mg imipenem and 750mg cilastatin power mixture for intramuscular injection

Intravenous

  • 250mg imipenem, 250mg cilastatin, and 10mg sodium bicarbonate power mixture for intravenous injection
  • 500mg imipenem, 500mg cilastatin, and 20mg sodium bicarbonate power mixture for intravenous injection

Mild infections

  • (fully susceptible) 250 mg IV every 6 hr; (moderately susceptible including P. aeruginosa) 500 mg IV every 6 hr

Moderate infections

  • (fully susceptible) 500 mg IV every 6-8 hr; (moderately susceptible including P. aeruginosa) 500 mg IV every 6 hr or 1 g IV every 8 hr

Severe, life-threatening infections

  • (fully susceptible) 500 mg IV every 6 hr; (moderately susceptible including P. aeruginosa) 1 g IV every 8 hr or 1 g IV every 6 hr; maximum 50 mg/kg/day or 4 g/day, whichever is lower

Cystic chronic injury or inflammation. সহজ বাংলা: অতিরিক্ত দাগের মতো টিস্যু তৈরি হওয়া।" data-rx-term="fibrosis" data-rx-definition="Fibrosis means excess scar-like tissue formation after chronic injury or inflammation. সহজ বাংলা: অতিরিক্ত দাগের মতো টিস্যু তৈরি হওয়া।">fibrosis

  • (12 years and older) up to 90 mg/kg/day IV divided every 6 hr; maximum 4 g/day

Urinary tract infections, uncomplicated

  • 250 mg IV every 6 hr

Urinary tract infections, complicated

  • 500 mg IV every 6 hr

Gynecologic infections

  • 500-750 mg IM every 12 hr

Intra-abdominal infections

  • 750 mg IM every 12 hr

Lower respiratory tract infections

  • 500-750 mg IM every 12 hr

Skin/skin structure infections

  • 500-750 mg IM every 12 hr

Side Effects of Imipenem

Most Common

  • pain, swelling, redness, bruising, or hardening where the medicine was injected;
  • nausea
  • vomiting
  • diarrhea
  • confusion
  • drooping eyelids
  • seizures
  • pain in the head or upper neck. সহজ বাংলা: মাথাব্যথা।" data-rx-term="headache" data-rx-definition="Headache means pain in the head or upper neck. সহজ বাংলা: মাথাব্যথা।">headache
  • redness, pain, or swelling at the injection site

Common 

  • severe diarrhea (watery or bloody stools) that may occur with or without fever and stomach cramps (may occur up to 2 months or more after your treatment)
  • hives
  • itching
  • rash
  • difficulty breathing or swallowing
  • blisters on the skin, mouth, nose, and eyes
  • sloughing (shedding) of skin
  • confusion
  • seizures

Rare

  • severe stomach pain, diarrhea that is watery or bloody;
  • upper stomach pain, loss of appetite;
  • jaundice (yellowing of the skin or eyes);
  • a seizure (convulsions);
  • fever; or
  • a light-headed feeling, like you might pass out.
  • dizziness, drowsiness;
  • nausea, vomiting, diarrhea; or
  • itching, rash.

Imipenem and cilastatin injection may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

Drug Interactions of Imipenem

  • amifampridine
  • aminophylline
  • anisindione
  • bcg
  • bupropion
  • cholera vaccine, live
  • cyclosporine
  • dicumarol
  • divalproex sodium
  • dyphylline
  • entecavir
  • estradiol
  • ethinyl estradiol
  • evening primrose
  • fluphenazine
  • ganciclovir
  • ginkgo
  • indium oxyquinoline in-111
  • iohexol
  • iopamidol
  • lindane topical
  • metrizamide
  • mycophenolate mofetil
  • mycophenolic acid
  • oxtriphylline
  • pemetrexed
  • polyethylene glycol 3350 with electrolytes
  • probenecid
  • theophylline
  • tramadol
  • typhoid vaccine, live
  • valganciclovir
  • valproic acid
  • warfarin

Pregnancy

Category C: Risk unknown. Human studies are inadequate.

Before using imipenem and cilastatin injection,

  • tell your doctor and pharmacist if you are allergic to imipenem or cilastatin; other carbapenem antibiotics such as doripenem (Doribax), ertapenem (Invanz), or meropenem (Merrem); local anesthetics such as bupivacaine (Exparel, Marcaine, Sensorcaine), etidocaine (Duranest), lidocaine, mepivacaine (Carbocaine, Prolocaine), or prilocaine (Citanest); cephalosporins such as cefaclor (Ceclor), cefadroxil (Duricef), or cephalexin (Keflex); other beta-lactam antibiotics such as penicillin or amoxicillin (Amoxil, Trimox, Wymox); any other medications; or any of the ingredients in imipenem and cilastatin injection. Ask your pharmacist or check the manufacturer’s patient information for a list of the ingredients.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: ganciclovir, probenecid (Probalan), or valproic acid (Depakene, Depakote). 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 brain lesions, seizures, or kidney disease.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while using imipenem and cilastatin injection, call your doctor.

References

Doctor visit helper

Prepare before seeing a doctor

A simple rural-patient checklist to help you explain symptoms clearly, ask better questions, and avoid unsafe self-treatment.

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

  • Drink safe fluids and monitor temperature.
  • In dengue-prone areas, discuss CBC and platelet count when fever persists or warning signs appear.
  • Use tepid sponging for high fever discomfort; avoid ice-cold bathing.

OTC medicine safety

  • For fever, common fever medicine may be discussed with a clinician or pharmacist.
  • Avoid aspirin/ibuprofen-like medicines in suspected dengue unless a doctor says it is safe.

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

  • Fever with breathing difficulty, confusion, repeated vomiting, bleeding, severe weakness, stiff neck, or dehydration 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.

For rural patients and family caregivers

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: Imipenem – Uses, Dosage, Side Effects, Interactions

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.

RX Patient Help

Ask a health question safely

Write your symptom story. A health professional or site editor can review it before any answer is prepared. This box is not for emergency care.

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

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

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