Meropenem: veterinary dose and monograph

At a glance

Drug class

Antibiotic

Also known as

Meronem, Merocrit, Penem

Species with doses

Dogs and Cats

General dose range

8–12 mg/kg SC q8–12h — check the species tables for the indication

Routes

SC, IV

Last reviewed

1 October 2026

Indications

• Documented multidrug-resistant Gram-negative infection (ESBL/AmpC E. coli, Klebsiella, resistant Pseudomonas)
• Severe sepsis/peritonitis unresponsive to first-line agents (culture-guided)
• Resistant complicated UTI / soft-tissue infection

Meropenem dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• MDR Gram-negative infection: Papich 5e: Enterobacteriaceae 10 mg/kg q8h IV, IM or SC. Plumb’s p.790 (Greene 2006; Papich 2002): systemic infections 12 mg/kg SC q8h or 24 mg/kg IV once daily; UTI 12 mg/kg SC q12h. Reserve for documented resistant infections (public-health stewardship).
• Pseudomonas / CNS infection: Papich 5e: Pseudomonas aeruginosa 30 mg/kg q8h IV, IM or SC. Plumb’s p.790 (Greene 2006): CNS infections 40 mg/kg IV or SC q8h (extrapolated from children; maximum 2 g per dose). Reduce frequency in renal failure.
• Constant-rate infusion: Papich 5e: 1 mg/kg IV followed by 1 mg/kg/h.

Cats

• MDR Gram-negative infection: Papich 5e: 10 mg/kg IM, SC or IV q12h. Plumb’s p.790: 8 mg/kg IV or SC q8h (Hawkins 2009); 12 mg/kg SC q8h systemic, q12h UTI (dogs and cats). Reserve for resistant infections.

Contraindications

Beta-lactam hypersensitivity (rare carbapenem cross-reactivity). Reduce dose in renal impairment (renally excreted — accumulation lowers seizure threshold). Routine/empiric use (reserve agent). Known hypersensitivity. Avoid with valproate (if ever used).

Adverse effects

• Injection-site reaction (less with SC than IV)
• GI upset
• Seizures (high dose / renal failure — lowers seizure threshold)
• Hypersensitivity; rare cytopenias

Drug interactions

• Valproic acid: meropenem dramatically lowers valproate levels (avoid)
• Probenecid: prolongs half-life
• Other nephrotoxins: additive in renal impairment
• Aminoglycosides: synergy but separate administration

Pregnancy and lactation

Limited veterinary data; carbapenems are used in human pregnancy for serious infection. Reserve for life-threatening resistant infection.

Monitoring

• Culture & sensitivity confirming an MDR organism BEFORE use (mandatory stewardship)
• Renal function (dose adjustment; seizure risk)
• Neurological status (seizures)
• Documented justification / antimicrobial stewardship records

Toxicity and overdose

Wide margin; the notable risk is dose-/accumulation-dependent CNS excitation and seizures, especially with renal impairment. Otherwise hypersensitivity and GI upset. Ecologically, its overuse selects for carbapenem-resistant Enterobacteriaceae — a critical-priority resistance.

Management: No specific antidote. Discontinue; control seizures with benzodiazepines; support with IV fluids and reduce/withhold dose in renal impairment (haemodialysis removes the drug). Treat hypersensitivity conventionally.

Clinical pearls

• A true last-resort antibiotic — use ONLY for culture-confirmed multidrug-resistant infections, never empirically
• Subcutaneous dosing works well in dogs/cats (good absorption, less phlebitis) — a practical advantage
• Reconstituted meropenem is unstable — prepare fresh and use promptly
• Reduce the dose in renal impairment to avoid seizure-threshold lowering
• Every use should be documented and justified — carbapenem resistance is a critical global threat

Mechanism of action

Carbapenem beta-lactam that binds multiple penicillin-binding proteins (especially PBP2/3), inhibiting cell-wall synthesis — bactericidal, time-dependent. Its compact structure penetrates Gram-negative porins efficiently and resists most beta-lactamases (including ESBLs and AmpC), explaining its exceptionally broad spectrum. (Carbapenemases are the key resistance mechanism that must be avoided.)

Formulations and products

• Injection 500 mg vial (reconstitute)
• Injection 1 g vial (reconstitute)
• Meronem — 500 mg / 1 g vial, Injection (reconstitute) (human-label)
• Merocrit / Penem — 500 mg / 1 g vial, Injection (human-label)

Storage

Powder vial: 15–30 °C. Reconstituted solution: use promptly — stability is limited (a few hours at room temperature; refrigerate per label). Do not freeze reconstituted drug.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other antibiotics

• Levofloxacin
• Lincomycin
• Linezolid
• Marbofloxacin
• Minocycline
• Mupirocin
• Neomycin
• Nitrofurantoin

Frequently asked questions