Meropenem Dosing
For adults with normal renal function, administer meropenem 500 mg IV every 8 hours for complicated skin/skin structure infections or 1 gram IV every 8 hours for intra-abdominal infections, with dose reductions required when creatinine clearance falls below 50 mL/min. 1
Adult Dosing
Standard Dosing (Normal Renal Function)
- Complicated skin/skin structure infections: 500 mg IV every 8 hours
- Intra-abdominal infections: 1 gram IV every 8 hours
- Pseudomonas aeruginosa infections: 1 gram IV every 8 hours (regardless of infection site)
- Administration: 15-30 minute infusion, or 3-5 minute bolus for 1 gram doses 1
Renal Impairment Adjustments
The FDA label provides clear guidance that must be followed 1:
| Creatinine Clearance | Dose | Interval |
|---|---|---|
| >50 mL/min | Standard dose | Every 8 hours |
| 26-50 mL/min | Standard dose | Every 12 hours |
| 10-25 mL/min | Half standard dose | Every 12 hours |
| <10 mL/min | Half standard dose | Every 24 hours |
Critical caveat: Use the Cockcroft-Gault equation to calculate creatinine clearance when only serum creatinine is available 1. Recent research confirms these recommendations are appropriate for patients with impaired renal function, but may be suboptimal for those with augmented renal clearance (CrCl ≥90 mL/min), who may require higher doses or continuous infusion 2.
Pediatric Dosing
Children ≥3 Months of Age (Normal Renal Function)
Weight-based dosing 1:
- Complicated skin/skin structure infections: 10 mg/kg every 8 hours (max 500 mg)
- For P. aeruginosa: 20 mg/kg every 8 hours (max 1 gram)
- Intra-abdominal infections: 20 mg/kg every 8 hours (max 1 gram) 3
- Meningitis: 40 mg/kg every 8 hours (max 2 grams)
- Administration: 15-30 minute infusion or 3-5 minute bolus
For children >50 kg, use adult dosing 1.
Infants <3 Months of Age (Intra-abdominal Infections Only)
Dosing is based on gestational age (GA) and postnatal age (PNA) 1:
| Patient Group | Dose | Interval |
|---|---|---|
| <32 weeks GA, PNA <2 weeks | 20 mg/kg | Every 12 hours |
| <32 weeks GA, PNA ≥2 weeks | 20 mg/kg | Every 8 hours |
| ≥32 weeks GA, PNA <2 weeks | 20 mg/kg | Every 8 hours |
| ≥32 weeks GA, PNA ≥2 weeks | 30 mg/kg | Every 8 hours |
Administration: 30-minute infusion only 1
Pediatric Renal Impairment
No established dosing exists for pediatric patients with renal impairment 1. Recent modeling suggests dose reductions to 10 mg/kg for moderate renal impairment and 7.5 mg/kg for severe renal impairment may be appropriate, but this requires clinical validation 4.
Special Populations and Considerations
Hemodialysis
The FDA label states inadequate information exists for dosing in hemodialysis patients 1. However, older pharmacokinetic data suggests dosing after each hemodialysis session, as dialysis significantly reduces meropenem half-life from 7.0 to 2.9 hours 5.
Augmented Renal Clearance
Important pitfall: Standard dosing is suboptimal in ICU patients with CrCl ≥90 mL/min 2. These patients may require increased doses (up to 6 g/day), more frequent administration, extended infusions, or continuous infusion to achieve pharmacodynamic targets 6, 7.
Continuous Infusion
Recent evidence strongly supports continuous infusion over intermittent dosing, showing 95.3% vs 49.5% probability of achieving pharmacodynamic targets 6. Recommended daily doses by continuous infusion:
- Moderate-severe renal impairment: 3 g/day
- Normal-mild renal impairment: 6 g/day
- Augmented renal clearance: 10.5 g/day 6
Key Clinical Pitfalls
- Do not co-administer with probenecid - inhibits renal excretion 1
- Avoid combination with valproic acid/divalproex - reduces valproate levels and increases seizure risk 1
- Maximize β-lactam doses when undrained abscesses may be present 3
- Monitor for seizures - particularly in patients with CNS disorders or renal dysfunction 1
- Adjust for actual renal function - not just baseline creatinine; critically ill patients often have dynamic renal function 2