Meropenem Dosing According to IDSA Guidelines
The standard IDSA-endorsed meropenem dose for adults with normal renal function is 1 gram intravenously every 8 hours, as consistently recommended across multiple IDSA-affiliated guidelines for serious infections including intra-abdominal infections and catheter-related bloodstream infections. 1
Standard Adult Dosing (Normal Renal Function)
For critically ill patients and healthcare-associated infections, meropenem 1 gram IV every 8 hours is the established regimen. 1 This dosing applies to:
- Critically ill patients with community-acquired intra-abdominal infections at risk for ESBL-producing Enterobacteriaceae 1
- Non-critically ill patients with healthcare-associated intra-abdominal infections at higher risk for multidrug-resistant organisms 1
- Critically ill patients with healthcare-associated intra-abdominal infections 1
Pediatric Dosing
For infants ≥3 months of age and children, the IDSA-endorsed dose is 20 mg/kg every 8 hours. 1
For neonates, age-based dosing is required 1:
- Postnatal age 0-7 days: 20 mg/kg every 12 hours
- Postnatal age >7 days and 1200-2000 g: 20 mg/kg every 12 hours
- Postnatal age >7 days and >2000 g: 20 mg/kg every 8 hours
Dosing for Multidrug-Resistant Organisms
When treating carbapenem-resistant Enterobacterales with meropenem MIC ≥8 mg/L, use extended infusion: 1 gram IV over 3 hours every 8 hours. 1, 2 This extended infusion strategy maximizes the time that free drug concentrations remain above the MIC, which is critical for beta-lactam efficacy 3, 2.
Renal Impairment Dosing Considerations
Meropenem requires dose adjustment in renal impairment, as up to 70% is excreted unchanged in urine and elimination half-life increases from approximately 1 hour in healthy volunteers to up to 13.7 hours in anuric patients. 4, 5
Renal Replacement Therapy
For patients on Continuous Renal Replacement Therapy (CRRT), use 1 gram every 8 hours to compensate for continuous drug removal. 2 CRRT removes 25-50% of meropenem, while continuous venovenous hemodiafiltration (CVVHDF) removes 13-53% 3, 2, 4.
For intermittent hemodialysis, administer meropenem after dialysis sessions, as approximately 50% is eliminated during dialysis. 2, 4 Administering before dialysis leads to premature drug removal and subtherapeutic levels 2.
For Sustained Low-Efficiency Dialysis (SLED), maintain the full 1 gram dose every 12 hours. 2 The dosing interval of every 12 hours is supported by the prolonged elimination half-life in renal impairment 2.
Critical Pharmacokinetic Principles
For beta-lactams like meropenem, the key parameter for efficacy is the time that plasma concentration remains above the pathogen's MIC (T>MIC), with optimal response in severe infections requiring T>MIC approaching 100%. 3 More frequent dosing (every 8 hours versus every 12 hours) with the same total daily dose provides better T>MIC coverage 3.
Common Pitfalls to Avoid
Do not reduce individual doses below 1 gram in renal impairment, as smaller doses may reduce efficacy despite altered clearance. 2 Instead, adjust the dosing interval.
Do not assume less frequent dosing is always better in renal impairment—this ignores the importance of maintaining adequate T>MIC 3.
Do not administer meropenem before dialysis sessions, as this causes premature drug removal and subtherapeutic levels 2.
Consider therapeutic drug monitoring in critically ill patients with renal impairment to ensure adequate exposure and avoid neurological toxicity (which typically occurs when trough concentrations exceed 64 mg/L) 2.