Meropenem
MERREM
Pronunciation: mer-oe-PEN-em
What it isPBP-inhibiting carbapenem; severe hospital-acquired, intra-abdominal, and CNS infections.
Why this oneBroad pseudomonal coverage, CNS penetration and much less seizure liability than imipenem make it the preferred carbapenem for meningitis.
What limits itNo MRSA cover. It lowers valproate levels enough to cause breakthrough seizures.
FDA-approved for
- serious infections (1996)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Complicated skin/skin structure infections | Adults | 500 mg IV q8h | 500 mg q8h (1 g q8h if P. aeruginosa) | 1 g q8h |
| Complicated intra-abdominal infections | Adults | 1 g IV q8h | 1 g q8h | 1 g q8h |
| cSSSI / cIAI / meningitis | Pediatric ≥3 mo | 10 / 20 / 40 mg/kg IV q8h | by infection type | 500 mg / 1 g / 2 g q8h |
Renal CrCl 26–50: full dose q12h; 10–25: half dose q12h; <10: half dose q24h
Hepatic Undefined
Dose q8h
Instructions
- IV infusion over 15–30 min, or IV bolus (5–20 mL) over 3–5 min (1 g doses)
- Do not mix with or add to solutions containing other drugs
- Avoid concomitant valproic acid/divalproex (reduces valproate levels, breakthrough seizures)
Available strengths
- inj 500 mg/vial
- inj 1, 2 g/vial
Contraindications
- Anaphylactic reactions to beta-lactams, or hypersensitivity to other carbapenem-class drugs
Cautions
- Serious/fatal hypersensitivity (anaphylactic) reactions
- Severe cutaneous adverse reactions (SJS, TEN, DRESS, EM, AGEP)
- Rhabdomyolysis
- Seizures/CNS effects, esp. with CNS disorders or renal impairment
- Reduced valproic acid levels → breakthrough seizures
- C. difficile-associated diarrhea
- Thrombocytopenia in renal impairment
Adverse reactions
- Headache
- Nausea/vomiting
- Diarrhea
- Constipation
- Anemia
- Rash
- Injection-site inflammation
Pregnancy Insufficient human data; no fetal toxicity/malformations in animals
Lactation Excreted in human milk; effects on infant/milk production unknown
Cost
| Strength | #/mo | generic $/unit | CostPlus | |
|---|---|---|---|---|
| 500 mg/vial | inj | per unit | not offered | |
| 1 g/vial | inj | per unit | $4.69/ea | not offered |
| 2 g/vial | inj | per unit | not offered |
Generic entryBy 2023
NO BOXED WARNINGS
Principal riskIt lowers valproate enough to cause breakthrough seizures
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilitySeizures and a profound interaction that can rapidly lower valproate concentrations.