Antibiotic (Carbapenem) Pregnancy: There are no or limited data from use in pregnant women; animal studies do not indicate reproductive toxicity. As a precautionary measure it is preferable to avoid meropenem during pregnancy. Small amounts are excreted in human milk - should not be used in breast-feeding women unless the potential benefit to the mother justifies the potential risk to the baby.

Meropenem

Brand names: Meronem

Meropenem is a broad-spectrum intravenous carbapenem antibacterial used for serious and hospital-acquired infections, including sepsis and intra-abdominal infection.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 500 mg or 1 g every 8 hours for severe pneumonia (including hospital and ventilator-associated pneumonia), complicated urinary tract infections, complicated intra-abdominal infections, intra- and post-partum infections and complicated skin and soft tissue infections; 2 g every 8 hours for acute bacterial meningitis and broncho-pulmonary infections in cystic fibrosis; 1 g every 8 hours for management of febrile neutropenic patients

Route: Intravenous infusion over approximately 15 to 30 minutes; alternatively doses up to 1 g may be given as an intravenous bolus injection over approximately 5 minutes

Frequency: Every 8 hours

Max: Up to 2 g three times daily in adults and adolescents

UK SPC section 4.2. The dose administered and the duration of treatment should take into account the type of infection, its severity and the clinical response. A dose of up to 2 g three times daily may be particularly appropriate for infections due to less susceptible bacterial species (e.g. Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter spp.) or very severe infections. There are limited safety data to support administration of a 2 g dose in adults as an intravenous bolus injection. Hepatic impairment: no dose adjustment necessary. Elderly: no dose adjustment required with normal renal function or creatinine clearance above 50 mL/min.

Paediatric dose

Route: Intravenous infusion over approximately 15 to 30 minutes; alternatively doses up to 20 mg/kg may be given as an intravenous bolus over approximately 5 minutes

Frequency: Every 8 hours

Max: Children over 50 kg body weight: the adult dose should be administered

UK SPC, children from 3 months to 11 years of age and up to 50 kg body weight, dose every 8 hours: severe pneumonia including hospital and ventilator-associated pneumonia 10 or 20 mg/kg; broncho-pulmonary infections in cystic fibrosis 40 mg/kg; complicated urinary tract infections 10 or 20 mg/kg; complicated intra-abdominal infections 10 or 20 mg/kg; complicated skin and soft tissue infections 10 or 20 mg/kg; acute bacterial meningitis 40 mg/kg; management of febrile neutropenic patients 20 mg/kg. Up to 40 mg/kg three times daily may be particularly appropriate for less susceptible species or very severe infections; there are limited safety data supporting a 40 mg/kg bolus dose. Children under 3 months: safety and efficacy not established and the optimal dose regimen has not been identified, though limited pharmacokinetic data suggest 20 mg/kg every 8 hours may be appropriate. There is no experience in children with renal impairment. Verify all paediatric doses against a children's formulary before prescribing.

Dose adjustments

Renal

Adjust the dose for adults and adolescents when creatinine clearance is less than 51 mL/min, based on the applicable unit dose of 500 mg, 1 g or 2 g: creatinine clearance 26-50 mL/min - one unit dose every 12 hours; 10-25 mL/min - half of one unit dose every 12 hours; less than 10 mL/min - half of one unit dose every 24 hours. There are limited data to support these dose adjustments for a unit dose of 2 g. Meropenem is cleared by haemodialysis and haemofiltration; the required dose should be administered after completion of the haemodialysis cycle. There are no established dose recommendations for patients receiving peritoneal dialysis.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

500 mg every 8 hours by intravenous infusion over 15 to 30 minutes for complicated skin and skin structure infections (cSSSI) for adult patients. When treating infections caused by Pseudomonas aeruginosa , a dose of 1 gram every 8 hours is recommended. ( 2.1 ) 1 gram every 8 hours by intravenous infusion over 15 minutes to 30 minutes for intra-abdominal infections for adult patients. ( 2.1 ) 1 gram every 8 hours by intravenous bolus injection (5 mL to 20 mL) over 3 minutes to 5 minutes for adult patients. ( 2.1 ) Dosage should be reduced in adult patients with renal impairment. ( 2.2 ) Recommended Meropenem for Injection, USP Dosage Schedule for Adult Patients with Renal Impairment …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2024-07-10. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Hypersensitivity to any other carbapenem antibacterial agent
Severe hypersensitivity (e.g. anaphylactic reaction, severe skin reaction) to any other type of beta-lactam antibacterial agent (e.g. penicillins or cephalosporins)

Side effects

Diarrhoea, vomiting, nausea, abdominal pain (common); antibiotic-associated and pseudomembranous colitis (uncommon)
Rash and pruritus (common); uncommonly toxic epidermal necrolysis, Stevens-Johnson syndrome, erythema multiforme, urticaria; DRESS and acute generalised exanthematous pustulosis (frequency not known)
Injection site inflammation and pain (common); thrombophlebitis (uncommon)
Thrombocythaemia (common); eosinophilia, thrombocytopenia, leucopenia, neutropenia, agranulocytosis, haemolytic anaemia (uncommon)
Increased transaminases, alkaline phosphatase and lactate dehydrogenase (common); drug-induced liver injury including hepatitis and liver failure (uncommon)
Headache (common); paraesthesiae (uncommon); convulsions and delirium (rare); angioedema and anaphylaxis (uncommon); rhabdomyolysis (frequency not known)

Interactions

Valproic acid / divalproex sodium: co-administration reduces valproic acid serum concentrations, potentially below the therapeutic range, increasing the risk of breakthrough seizures - generally not recommended; consider a non-carbapenem antibacterial (US labelling; UK SPC section 4.5 not captured in the source bundle)
Probenecid: competes with meropenem for active tubular secretion, increasing meropenem plasma concentrations - co-administration not recommended (US labelling; UK SPC section 4.5 not captured in the source bundle)

Clinical monograph

How it works

It is a beta-lactam that inhibits bacterial cell-wall synthesis by binding penicillin-binding proteins; it is stable against many beta-lactamases, giving broad activity.

Prescribing in practice

Reserve for serious infection and prescribe under local antimicrobial stewardship to limit carbapenem resistance.
Meropenem lowers plasma valproate levels and can cause loss of seizure control, so this combination is generally avoided.
It is renally cleared (dose reduction needed in renal impairment), seizures occur rarely, and cross-reactivity in penicillin allergy is low but possible.

Monitoring

Monitor renal function and clinical response; watch for neurological effects such as seizures, particularly in renal impairment or pre-existing CNS disease.

Counselling the patient

Report any twitching, confusion or seizures, and any rash, swelling or difficulty breathing.
Report severe, persistent or bloody diarrhoea, which may occur during or after treatment.

Evidence & guidelines

A standard carbapenem for severe and resistant Gram-negative infection; use should follow local antimicrobial guidance to preserve activity.

Reference: PHE Carbapenem Guidance; MERINO trial; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways