Meropenem Dosing and Treatment Duration for Severe Bacterial Infections
For severe bacterial infections, administer meropenem 1 gram IV every 8 hours via extended infusion over 3 hours, with treatment duration of 5-7 days based on clinical response and source control adequacy. 1, 2
Standard Dosing Regimens
Adult Patients with Normal Renal Function
- Complicated intra-abdominal infections: 1 gram IV every 8 hours 3
- Complicated skin and soft tissue infections: 500 mg IV every 8 hours (standard) or 1 gram IV every 8 hours when Pseudomonas aeruginosa is suspected or documented 3, 4
- Carbapenem-resistant Enterobacteriaceae (CRE) infections: 1 gram IV every 8 hours by extended infusion (3 hours) as part of combination therapy 1, 2
- Carbapenem-resistant Acinetobacter baumannii (CRAB): 2 grams IV every 8 hours when MIC ≤8 mg/L, as part of combination therapy 1
Administration Method
- Standard infusion: 15-30 minutes for routine infections 3
- Extended infusion: 3 hours when MIC ≥8 mg/L or for CRE infections to optimize pharmacodynamic targets 1, 2
- Bolus injection: 3-5 minutes for doses up to 1 gram (acceptable alternative) 3
- No loading dose required for meropenem, unlike colistin or tigecycline 1
Pediatric Dosing
Children ≥3 Months of Age
- Complicated skin/soft tissue infections: 10 mg/kg every 8 hours (maximum 500 mg per dose) 3
- Complicated intra-abdominal infections: 20 mg/kg every 8 hours (maximum 1 gram per dose) 3
- Bacterial meningitis: 40 mg/kg every 8 hours (maximum 2 grams per dose) 3
- For children >50 kg, use adult dosing 3
Infants <3 Months of Age (Complicated Intra-abdominal Infections Only)
- <32 weeks gestational age (GA) and <2 weeks postnatal age (PNA): 20 mg/kg every 12 hours 3
- <32 weeks GA and ≥2 weeks PNA: 20 mg/kg every 8 hours 3
- ≥32 weeks GA and <2 weeks PNA: 20 mg/kg every 8 hours 3
- ≥32 weeks GA and ≥2 weeks PNA: 30 mg/kg every 8 hours 3
Renal Dose Adjustments
Dosing must be reduced when creatinine clearance falls below 50 mL/min: 3
- CrCl 26-50 mL/min: Standard dose every 12 hours 3
- CrCl 10-25 mL/min: Half the standard dose every 12 hours 3
- CrCl <10 mL/min: Half the standard dose every 24 hours 3
- Inadequate data exists for hemodialysis or peritoneal dialysis patients 3
Treatment Duration
The Infectious Diseases Society of America recommends 5-7 days for most complicated infections, individualized based on: 1, 2
- Adequacy of source control (surgical drainage, debridement) 1
- Clinical response to therapy 1, 2
- Resolution of fever and leukocytosis 1
- For cholecystitis with cholecystectomy: Discontinue within 24 hours if no infection extends beyond the gallbladder wall 1
Optimization Strategies for Resistant Organisms
When to Use Extended Infusion
Extended 3-hour infusion is critical when: 1, 2
- Treating CRE infections 1, 2
- MIC ≥8 mg/L for the causative pathogen 1, 2
- Critically ill patients with healthcare-associated infections 2
Combination Therapy Considerations
- CRE bloodstream infections: Meropenem 1 gram IV every 8 hours (extended infusion) plus a second active agent based on susceptibility testing 5, 2
- CRAB infections: High-dose meropenem (2 grams every 8 hours) plus colistin when meropenem MIC ≤8 mg/L 1
- Newer agents preferred as monotherapy when susceptible: meropenem-vaborbactam 4 grams IV every 8 hours for KPC-producing CRE 1, 2
Common Pitfalls to Avoid
- Do not combine meropenem with piperacillin-tazobactam: This represents redundant beta-lactam coverage that violates antimicrobial stewardship principles 6
- Meropenem lacks activity against: MRSA and VRE—add vancomycin or linezolid if these pathogens are suspected 1
- Do not use standard infusion times for resistant organisms: Extended infusion is essential for adequate time above MIC when treating organisms with MIC ≥8 mg/L 1, 2
- Adjust for renal function: Failure to reduce dosing in renal impairment increases seizure risk 3