What is the recommended dose and use of Meropenem for treating bacterial infections?

Meropenem Dosing and Clinical Use

Standard Dosing for Common Infections

For complicated intra-abdominal infections, administer meropenem 1 gram IV every 8 hours as effective monotherapy. 1, 2, 3

Adult Dosing by Indication

• Complicated intra-abdominal infections: 1 gram IV every 8 hours 1, 3
• Complicated skin and skin structure infections: 500 mg IV every 8 hours (or 1 gram every 8 hours if P. aeruginosa suspected) 3
• Nosocomial pneumonia: 1-2 grams IV every 8 hours 4, 5

Administration Method

• Standard infusion: 15-30 minutes for routine infections 3
• Bolus injection: 3-5 minutes acceptable for 1 gram doses 3
• No loading dose required for meropenem in any clinical scenario 1

Optimized Dosing for Resistant Organisms

For carbapenem-resistant Enterobacteriaceae (CRE) infections, use meropenem 1 gram IV every 8 hours by extended infusion (3 hours) as part of combination therapy. 1, 2

Extended Infusion Strategy

• Use 3-hour extended infusion when:

  • Treating CRE infections 1, 2
  • Meropenem MIC ≥8 mg/L 1, 6
  • Critically ill patients with healthcare-associated infections 1, 2

• Rationale: Extended infusion optimizes the percentage of time drug levels remain above MIC, the key pharmacodynamic parameter for beta-lactam efficacy 7

Carbapenem-Resistant Acinetobacter baumannii (CRAB)

• For CRAB with meropenem MIC <8 mg/L: Consider high-dose extended-infusion meropenem (2 grams every 8 hours over 3 hours) as part of combination therapy with two in vitro active agents 8, 6
• Critical caveat: Do NOT use polymyxin-meropenem combination for CRAB infections—two high-quality RCTs (AIDA and OVERCOME) showed no benefit over colistin monotherapy 8

Pediatric Dosing

Children ≥3 Months of Age

• Complicated skin/soft tissue infections: 10 mg/kg every 8 hours (max 500 mg) 3
• Complicated intra-abdominal infections: 20 mg/kg every 8 hours (max 1 gram) 3
• Meningitis: 40 mg/kg every 8 hours (max 2 grams) 3
• For children >50 kg: Use adult dosing 3

Infants <3 Months of Age

• <32 weeks gestational age (GA), <2 weeks postnatal age (PNA): 20 mg/kg every 12 hours 3
• <32 weeks GA, ≥2 weeks PNA: 20 mg/kg every 8 hours 3
• ≥32 weeks GA, <2 weeks PNA: 20 mg/kg every 8 hours 3
• ≥32 weeks GA, ≥2 weeks PNA: 30 mg/kg every 8 hours 3

Renal Dose Adjustment

Reduce meropenem dose when creatinine clearance ≤50 mL/min. 3

• CrCl 26-50 mL/min: Standard dose every 12 hours 3
• CrCl 10-25 mL/min: Half dose every 12 hours 3
• CrCl <10 mL/min: Half dose every 24 hours 3
• Hemodialysis/peritoneal dialysis: Inadequate data available 3

Treatment Duration

Treat complicated intra-abdominal infections for 5-7 days, based on source control adequacy and clinical response. 1, 2

• Cholecystitis with cholecystectomy: Discontinue within 24 hours if no infection beyond gallbladder wall 1
• General principle: Duration depends on infection site, source control, and clinical improvement rather than arbitrary timeframes 1, 2

Spectrum of Activity

Effective Against

• Methicillin-susceptible Staphylococcus aureus (MSSA) 1
• Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae 4, 5
• AmpC-producing Enterobacteriaceae 4, 5
• Pseudomonas aeruginosa (though resistance may emerge during therapy) 9, 10
• Anaerobes 4, 9

NOT Effective Against

• Methicillin-resistant Staphylococcus aureus (MRSA) 1
• Vancomycin-resistant enterococci (VRE) 1
• Stenotrophomonas maltophilia (typically resistant) 9

Critical Clinical Pearls

• Meropenem has lower seizure risk than imipenem, making it the only carbapenem approved for bacterial meningitis 4, 10
• Does not require cilastatin (unlike imipenem) because it is stable to renal dehydropeptidase-I 9, 10
• Therapeutic drug monitoring (TDM) should be considered in critically ill patients and those with renal impairment to optimize dosing 7
• For meropenem-vaborbactam: Use 4 grams IV every 8 hours for KPC-producing CRE when susceptible 1, 2