Drug reference

Meropenem

Carbapenem · Antibiotic

Also known as Meropenem Trihydrate

START

Confirm infection and source; obtain cultures before first dose if feasible. Baseline renal function, CBC, LFTs. Check beta-lactam allergy history (cross-reactivity ~1% with penicillin anaphylaxis).

TYPICAL MAX

2 g IV q8h (6 g/day) for meningitis/severe sepsis. Do not exceed in patients with CrCl <50 without dose adjustment.

STOP IF

Severe hypersensitivity (anaphylaxis), seizures unresponsive to anticonvulsants, severe CDAD, persistent neutropenia, lack of clinical response after 72 hours with susceptible organism

WATCH

Renal function (adjust dose if CrCl <50), seizure threshold (especially meningitis/renal impairment/CNS disease), CDAD (diarrhea), CBC (neutropenia with prolonged use), LFTs

CDSCO approvedSchedule HJan AushadhiATC J01DH02

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 30min · Immediate (IV); 48-72 h (clinical)
PEAK: 30min · End of 30-min infusion (Cmax ~25 μg/mL)
t½: 1h · ~1 h (normal); 6-10 h (ESRD)
DURATION: 8h · 8 h (q8h dosing); extended infusion 3-4 h preferred

EXCRETION

~70% renal unchanged; 20% as inactive metabolite

route + CYP

INTERACTIONS

5 major

SEVERE in our sources

PREGNANCY

FDA PLLR: Animal studies showed no teratogenic effects. Limited human data. Crosses placenta. Use during pregnancy only if clearly needed. Generally considered safe in pregnancy (Category B in old system).

FDA category + note

Top interactionssee all 10 →

BupropionSevereDatabaseDDInter
IohexolSevereDatabaseDDInter
IopamidolSevereDatabaseDDInter
TramadolSevereDatabaseDDInter

Available in India

1,000 branded formulations and 118 fixed-dose combinations. Look up specific brands in the Drugs workspace.

Jan Aushadhi — generic available at GoI pharmacies

Mechanism

Meropenem is a broad-spectrum carbapenem antibiotic that exerts bactericidal activity by inhibiting bacterial cell wall synthesis. It binds with high affinity to penicillin-binding proteins (PBPs), particularly PBP-2 and PBP-3, preventing cross-linking of peptidoglycan chains and leading to osmotic lysis of the bacterial cell. Its zwitterionic structure (1β-methyl substitution) confers stability against most beta-lactamases (including extended-spectrum beta-lactamases, ESBLs) and renal dehydropeptidase-I (DHP-I), eliminating the need for a DHP-I inhibitor like cilastatin.

Indications

Complicated intra-abdominal infections (with metronidazole for anaerobic coverage)Complicated skin and skin structure infections (cSSSI)Bacterial meningitis (pediatric and adult)Hospital-acquired/ventilator-associated pneumonia (HAP/VAP)Complicated urinary tract infections (including pyelonephritis)Septicemia/bacteremiaFebrile neutropenia (empiric monotherapy)Polymicrobial infections (broad anaerobic + aerobic gram-negative/positive coverage except MRSA and Enterococcus)

Dosing

Adult: cSSSI: 500 mg IV q8h. Intra-abdominal: 1 g IV q8h (with metronidazole). Meningitis: 2 g IV q8h. HAP/VAP: 1-2 g IV q8h. Febrile neutropenia: 1 g IV q8h. UTI: 500 mg-1 g IV q8h. Infuse over 15-30 min (or bolus 3-5 min for doses ≤1 g). Extended infusion (3-4 hours) may improve outcomes in critically ill/sepsis.
Pediatric: ≥3 months: cSSSI 10 mg/kg IV q8h; intra-abdominal 20 mg/kg IV q8h; meningitis 40 mg/kg IV q8h (max 2 g/dose). >50 kg: adult dosing.
Renal adjustment: CrCl >50: full dose q8h. CrCl 26-50: full dose q12h. CrCl 10-25: 50% dose q12h. CrCl <10: 50% dose q24h. HD: give dose after dialysis (meropenem is dialyzable). CRRT: 1-2 g q8-12h depending on effluent rate.
Hepatic adjustment: No dosage adjustment necessary in hepatic impairment.
Geriatric: No adjustment for age alone if renal function normal. Adjust based on CrCl. Monitor for CNS effects (seizures) in elderly with renal impairment.
Max dose: 2 g/dose; 6 g/day (meningitis, severe sepsis)

Pharmacokinetics

Onset

Rapid bactericidal activity; clinical response typically within 48-72 hours for susceptible infections.

Peak effect

IV infusion: Cmax ~25 μg/mL (1 g dose). Peak at end of 30-min infusion.

Duration

Time-dependent killing — %fT>MIC is the PK/PD parameter predicting efficacy. Prolonged/extended infusion (3-4 hours) optimizes %fT>MIC.

Half-life

~1 hour in normal renal function; 2-4 hours in moderate renal impairment; 6-10 hours in severe renal impairment/ESRD.

Bioavailability

Not absorbed orally (IV only).

Protein binding

Very low: ~2% (non-saturable, concentration-independent).

Metabolism

Minimal hepatic metabolism (~20% via hydrolysis of beta-lactam ring by dehydropeptidase-I to open-ring metabolite, which is microbiologically inactive).

Excretion

Primarily renal: ~70% excreted unchanged in urine within 12 hours; ~20% as inactive open-ring metabolite. Fecal: ~2%.

Contraindications

Hypersensitivity to meropenem, other carbapenems (imipenem, doripenem, ertapenem), or beta-lactam antibiotics (cross-reactivity risk ~1-5% with penicillin allergy)
Patients who experienced anaphylaxis to penicillins or cephalosporins (relative — evaluate risk-benefit; cross-reactivity ~1% with IgE-mediated reactions)
No other absolute contraindications

Side effects

Common

Injection site phlebitis/thrombophlebitisDiarrhea, nausea, vomitingHeadacheRash (maculopapular, urticarial)Elevated liver enzymes (transient)Thrombocytosis

Serious

Seizures (0.7% in immunocompetent adults; higher in meningitis, renal impairment, CNS lesions, or doses >6 g/day)
Clostridioides difficile-associated diarrhea (CDAD) — all broad-spectrum antibiotics
Severe hypersensitivity reactions (anaphylaxis, angioedema, SJS/TEN — rare)
Acute interstitial nephritis
Hematologic: neutropenia, thrombocytopenia, eosinophilia, positive Coombs test
Hepatotoxicity (transient increases in ALT/AST, bilirubin)
Neutropenia (prolonged use >2 weeks)

Pregnancy & lactation

Pregnancy

Lactation

Excreted in breast milk in low concentrations (~0.5% of maternal dose). Compatible with breastfeeding per AAP. Monitor infant for diarrhea, candidiasis, or rash.

Drug interactions

Bupropion

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Iohexol

Severe

Database

Clinical effect not specified

Source: DDInter

Iopamidol

Severe

Database

Clinical effect not specified

Source: DDInter

Tramadol

Severe

Database

Source: DDInter

Valproic Acid

Severe

Database

Carbapenems (including meropenem) significantly reduce valproic acid serum concentrations by 50-100% within 24-48 hours via inhibition of intestinal absorption and possibly increased hepatic clearance. This can precipitate breakthrough seizures in patients controlled on valproate.

Avoid combination if possible in seizure patients. If unavoidable, monitor valproic acid levels every 1-2 days; increase valproate dose or add alternative anticonvulsant. Consider alternative antibiotic (e.g., piperacillin-tazobactam, cefepime).

Source: Kimi deep-research + Cla

Ganciclovir

Moderate

Database

Additive risk of seizures. Both drugs can lower seizure threshold; concurrent use may increase CNS toxicity.

Use caution in patients with CNS disorders or renal impairment. Monitor for signs of CNS toxicity (tremors, myoclonus, seizures). Have anticonvulsant readily available.

Source: Kimi deep-research + Cla

Live Oral Typhoid Vaccine

Moderate

Database

Antibiotics may reduce efficacy of live bacterial vaccines by killing the attenuated vaccine organisms.

Defer live oral typhoid vaccine until ≥24 hours after completing meropenem course. Use alternative vaccination timing.

Source: Kimi deep-research + Cla

Mycophenolate Mofetil

Moderate

Database

Decreased mycophenolic acid levels, potentially leading to reduced immunosuppression and increased risk of transplant rejection.

Monitor mycophenolic acid levels closely. Adjust MMF dose as needed. Consider alternative antibiotics if possible.

Source: DDInter

Oral Anticoagulants

Moderate

Database

Meropenem may reduce vitamin K synthesis by gut flora and/or affect platelet function, potentiating warfarin's anticoagulant effect.

Monitor INR closely (every 2-3 days) when starting or stopping meropenem. Anticipate warfarin dose adjustment.

Source: Kimi deep-research + Cla

Probenecid

Moderate

Database

Probenecid competitively inhibits renal tubular secretion of meropenem, increasing plasma concentrations and half-life.

May be used therapeutically to prolong meropenem exposure. If unintended, monitor for increased adverse effects (seizures, GI upset). No routine dose adjustment needed.

Source: Kimi deep-research + Cla

2 additional unreviewed or low-confidence interactions hidden because their provenance or source detail is insufficient.