Antibiotic · Beta-lactam · Carbapenem

Meropenem (Merrem)

Also called Merrem

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · From the Reference tab of the app

Indications

Complicated skin and skin-structure infection, adults and children 3 months and up (label)
Complicated intra-abdominal infection (label)
Bacterial meningitis in children 3 months and up (label); adult and post-neurosurgical meningitis off-label
ESBL-producing E. coli or Klebsiella bacteremia, where it beat piperacillin-tazobactam on 30-day mortality (MERINO 2018; off-label)
Empiric sepsis, hospital-acquired pneumonia and febrile neutropenia when resistant gram-negatives are likely (off-label)

Dosing

Where	Dose
Antimicrobials	Meropenem: Reduce at CrCl 50 or less

On the quick cards

Mechanism of action

Meropenem is a carbapenem that binds penicillin-binding proteins, mainly PBPs 2, 3 and 4 in E. coli and Pseudomonas and PBPs 1, 2 and 4 in S. aureus (label), blocking peptidoglycan cross-linking so the cell wall fails. Its trans-hydroxyethyl side chain makes it stable to most beta-lactamases, including ESBLs and AmpC, and its 1-β-methyl group protects it from renal dehydropeptidase-I, so unlike imipenem it needs no cilastatin. Resistance comes from porin loss, efflux pumps, altered PBPs and carbapenemases (label).

Pharmacology

Infectious: broad gram-negative activity including Pseudomonas, plus anaerobes and MSSA; no activity against MRSA (label)
CNS: seizures in 0.7% of 2,904 adults, all with risk factors; risk is higher with CNS disease, meningitis or renal impairment (label)
GI: diarrhea 4.8%, nausea and vomiting 3.6% (label); C. difficile
Hematologic: thrombocytopenia in renal impairment, without reported bleeding (label)
Skin and CNS: rash 1.9%, headache 2.3% (label)

Pharmacokinetics

Peak	About 49 mcg/mL after 1 g over 30 min (label)
Half-life	About 1 h (label)
Protein binding	About 2% (label)
Metabolism	About 28% to an inactive metabolite (label)
Elimination	About 70% unchanged in urine within 12 h; feces 2% (label)
Renal dosing	CrCl 26–50: every 12 h; 10–25: half dose every 12 h; under 10: half dose every 24 h (label)
Dialysis	Removed by hemodialysis (label)
Infusion	15–30 min, or 1 g as a 3–5 min bolus (label); extended infusion off-label

Chemistry

A 1-β-methyl carbapenem with a dimethylcarbamoyl-pyrrolidinylthio side chain; C₁₇H₂₅N₃O₅S·3H₂O, MW 437.52 as the trihydrate (label)
White to pale yellow crystalline powder; sodium 3.92 mEq per gram; reconstituted pH 7.3–8.3 (label)

Adverse effects and cautions

In the one-pagers

Neuro: ICP and StrokeEVD management: leveling, drainage, clamping, infection: Ventriculitis complicates roughly 5–10% of drains; risk rises with IVH or SAH, CSF leak, frequent access and days in place. The NCS 2016 EVD consensus recommends antimicrobial-impregnated catheters, one periprocedural antibiotic dose rather than continuous prophylaxis, CSF sampling only when clinically indicated, and no routine catheter exch

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Sources

FDA label: Meropenem for Injection (Hospira, 2022)
Harris 2018 (MERINO trial)

For education and exam preparation only. Follow your institution’s protocols. Typical adult values for study. Follow your local protocols and medical direction.