Meropenem !

A broad-spectrum intravenous carbapenem for serious hospital infections, intra-abdominal sepsis and meningitis; it can drop valproate levels.

Updated 2026-11-01

Class: Carbapenems
Enzyme: Penicillin-binding proteins (bacterial transpeptidases)
ATC code: J01DH02
WHO Model List of Essential Medicines

Penicillin-binding proteins (bacterial transpeptidases)Meropenem

The figure shows meropenem bound to penicillin-binding protein 3 of Pseudomonas aeruginosa, one of its main targets.

Target in 3D: Penicillin-binding proteins (bacterial transpeptidases). PDB structure 3PBR (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Meropenem crosses the bacterial envelope and acylates penicillin-binding proteins (in Escherichia coli and Pseudomonas aeruginosa mainly PBP2, PBP3 and PBP4). Cross-linking of the wall stops and the bacterium lyses. It resists most β-lactamases, including ESBL, but is destroyed by carbapenemases.

Crosses porins of the outer membrane
Acylates PBPs and stops wall cross-linking
Resists ESBL; destroyed by carbapenemases
The wall fails and the bacterium lyses

Pharmacokinetics

Absorption: Intravenous only.
Distribution: Very low protein binding; reaches the cerebrospinal fluid well enough to treat meningitis.
Elimination: Mostly by the kidney; probenecid blocks its secretion.
Half-life: About 1 hour with normal kidney function.

Indications

Complicated intra-abdominal infections such as complicated appendicitis and peritonitis. Peritonitis →
Bacterial meningitis in children. Bacterial meningitis →
Complicated skin and soft-tissue infections.
Serious hospital-onset infections when resistant gram-negatives (such as ESBL producers) are suspected. Hospital-acquired and ventilator-associated pneumonia →

Adverse effects

Common

Diarrhoea, nausea, vomiting
Headache, rash, itching
Inflammation at the injection site

Contraindications

Hypersensitivity to meropenem or other drugs of the class
Anaphylaxis to any β-lactam

Key interactions

Valproic acid / divalproex: Valproate levels fall below the therapeutic range and seizures may return; the combination is generally avoided.
Probenecid: Blocks renal excretion and raises meropenem levels; not recommended.

What is monitored

Kidney function (to adjust the regimen)
Neurological status in patients with CNS disease or kidney failure
Valproate levels if the combination cannot be avoided
Platelets in kidney impairment

Administration and safety

Intravenous infusion or slow injection after reconstitution; the prepared solution is used within the stability time on the label.
Some protocols use prolonged infusions to keep levels above the MIC longer.
Look-alike names with other «-penems»: check the exact carbapenem ordered.

Nursing care

Before the first dose: ask about β-lactam allergy and whether the patient takes valproic acid.
Watch for allergic reactions during the first doses.
Watch for confusion, myoclonus or seizures, especially with kidney failure.
Teaching: report watery or bloody diarrhoea, rash, and that it may affect alertness.

Pregnancy and breastfeeding

Human data are insufficient to define a risk; animal studies showed no malformations. It is used in pregnancy when clearly needed.

Test yourself

Think of the answer, then tap the question to see it.

Why is meropenem preferred over imipenem when a carbapenem is needed for meningitis?

It is less likely to cause seizures while reaching the cerebrospinal fluid well.

How do carbapenems lower valproic acid levels?

They are thought to block the hydrolysis of valproate glucuronide back to valproic acid, so the active drug falls quickly.

Which killing parameter best predicts meropenem efficacy?

The percentage of the dosing interval that the free drug stays above the MIC (time-dependent killing).

Does meropenem cover MRSA?

No. It covers methicillin-susceptible staphylococci only; MRSA needs a drug such as vancomycin or linezolid.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: DailyMed - MEROPENEM injection, powder, for solution (DailyMed (U.S. National Library of Medicine), 2026); Meropenem Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 58 (McGraw Hill, 2023); RCSB PDB - 3PBR: Crystal structure of PBP3 complexed with meropenem (RCSB Protein Data Bank, 2026).

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Representative model, for educational purposes only.