Meropenem Dosing and Clinical Use
Standard Adult Dosing Regimens
For most serious infections in adults with normal renal function, administer meropenem 1 gram IV every 8 hours; increase to 2 grams IV every 8 hours for meningitis, severe pneumonia, or infections with organisms having MIC ≥8 mg/L. 1, 2, 3
Infection-Specific Dosing
- Complicated intra-abdominal infections: 1 gram IV every 8 hours for 5-7 days 1, 2, 3
- Hospital-acquired/ventilator-associated pneumonia: 1-2 grams IV every 8 hours for ≥7 days 2, 3
- Bloodstream infections/sepsis: 1 gram IV every 8 hours for 7-14 days 2, 3
- Meningitis (Enterobacteriaceae): 2 grams IV every 8 hours for 21 days 3
- Complicated urinary tract infections: 1 gram IV every 8 hours for 5-7 days 2
- Necrotizing skin/soft tissue infections: 1-2 grams IV every 8 hours for 7-14 days (must combine with MRSA coverage) 3
Extended Infusion Strategy
Administer meropenem as a 3-hour extended infusion when treating carbapenem-resistant Enterobacteriaceae or any organism with MIC ≥8 mg/L to optimize time above MIC. 2, 3 Standard infusions over 30 minutes are acceptable for susceptible organisms with lower MICs 1, 2.
Pediatric Dosing
Administer meropenem 60 mg/kg/day divided every 8 hours (maximum 6 grams/day) for children with complicated intra-abdominal infections, pneumonia, or other serious infections. 1
- Neonates with necrotizing enterocolitis: Meropenem is an acceptable monotherapy option alongside ampicillin-gentamicin-metronidazole or ampicillin-cefotaxime-metronidazole regimens 1
- Meningitis (pediatric): Use higher end of dosing range (up to 120 mg/kg/day divided every 8 hours) 1
Renal Dose Adjustments
Reduce meropenem dose or extend dosing interval based on creatinine clearance, but maintain full 1 gram doses when possible by extending intervals rather than reducing individual doses. 4
Dosing by Creatinine Clearance
- CrCl 26-50 mL/min: 1 gram every 12 hours 4
- CrCl 10-25 mL/min: 500 mg every 12 hours 4
- CrCl <10 mL/min: 500 mg every 24 hours 4
Dialysis Considerations
- Intermittent hemodialysis: Administer 500 mg-1 gram after each dialysis session, as approximately 50% is removed during dialysis 4
- CRRT (CVVH/CVVHD/CVVHDF): 1 gram every 8-12 hours due to 25-50% drug removal; therapeutic drug monitoring strongly recommended 4
- SLED: 1 gram every 12 hours to preserve concentration-dependent killing 4
Critical pitfall: Never administer meropenem before hemodialysis sessions, as this causes premature drug removal and subtherapeutic levels 4.
Indications for Carbapenem Use
Do not use meropenem empirically for community-acquired infections unless the patient has known ESBL colonization within 3 months AND presents with severe sepsis or septic shock. 1
When to Use Carbapenems for Hospital-Acquired Infections
Prescribe meropenem empirically only when at least 2 of the following criteria are present 1:
- Prior third-generation cephalosporin, fluoroquinolone, or piperacillin-tazobactam use within 3 months
- Known ESBL or ceftazidime-resistant Pseudomonas colonization within 3 months
- Hospitalization within the last 12 months
- Nursing facility resident with indwelling catheter or gastrostomy tube
- Ongoing institutional outbreak of multidrug-resistant organisms requiring carbapenem
After culture results return, de-escalate to narrower-spectrum agents whenever possible according to susceptibility data and infection site. 1
Contraindications and Precautions
- Absolute contraindication: Severe hypersensitivity to carbapenems 5, 6
- Relative contraindication: History of severe beta-lactam allergy (anaphylaxis, Stevens-Johnson syndrome) 1
- Seizure risk: Meropenem has the lowest pro-convulsive activity among carbapenems, but neurological toxicity occurs when trough concentrations exceed 64 mg/L 2, 4
- CNS infections: Unlike imipenem, meropenem is safe for meningitis treatment 5, 6, 7
Therapeutic Drug Monitoring
Obtain therapeutic drug monitoring in ICU patients with renal replacement therapy, suspected pharmacokinetic variability, or clinical signs of toxicity (altered mental status, seizures). 2, 4
- Target: Free drug concentration above pathogen MIC for ≥40% of dosing interval (≥70% for critically ill patients) 3
- Toxicity threshold: Trough concentration >64 mg/L associated with neurological deterioration 2
Alternative Agents
When meropenem is contraindicated or carbapenem-sparing is desired 1:
- For ESBL-producing Enterobacteriaceae: Piperacillin-tazobactam 3.375-4.5 grams IV every 6 hours (if MIC ≤16 mg/L)
- For severe beta-lactam allergy: Ciprofloxacin 400 mg IV every 8-12 hours plus metronidazole 500 mg IV every 8 hours, or aztreonam 2 grams IV every 8 hours plus metronidazole
- For Pseudomonas without ESBL: Cefepime 2 grams IV every 8 hours or ceftazidime 2 grams IV every 8 hours
- For anaerobic coverage alone: Metronidazole 500 mg IV every 8 hours
Critical Pitfalls to Avoid
- Never use meropenem monotherapy for necrotizing infections—MRSA coverage with vancomycin or linezolid is mandatory 3
- Do not use meropenem for MRSA or VRE—it lacks activity against these organisms 3
- Avoid underdosing in ICU patients with normal renal function—increased clearance and volume of distribution require higher doses (2 grams every 8 hours) 2
- Do not delay surgical debridement while awaiting antibiotic effect in necrotizing infections—surgery is primary treatment 3
- Never stop antibiotics at 5 days for necrotizing infections—minimum 7-10 days required 3
- Do not administer before dialysis—give post-dialysis to prevent premature removal 4
Duration of Therapy
Treat for 5-7 days for most community-acquired infections with adequate source control; extend to 7-14 days for bloodstream infections, severe pneumonia, or inadequate source control. 2, 3
Extended Duration Indications (10-21 days)
- Meningitis caused by Enterobacteriaceae or Listeria: 21 days 3
- Deep-seated infections, organ abscesses, or osteomyelitis: 14-21 days 3
- Inadequate source control or persistent systemic toxicity: Continue until clinical resolution 3
- Melioidosis (Burkholderia pseudomallei): 14 days intensive phase, then 3-6 months oral eradication phase with trimethoprim-sulfamethoxazole 3