Meropenem Loading Dose
Meropenem does not require a loading dose for standard administration in patients with normal renal function. 1
Standard Dosing Without Loading Dose
The evidence consistently demonstrates that meropenem is administered without a loading dose across multiple clinical scenarios:
For carbapenem-resistant Acinetobacter baumannii infections: Meropenem 2 g IV every 8 hours is recommended without any loading dose 1
For general severe infections in ICU patients: The standard regimen is meropenem 2 g every 8 hours with no loading dose specified 1
For complicated intra-abdominal infections: 1 gram IV every 8 hours is recommended without a loading dose 2, 3, 4
Extended Infusion Considerations (Not Loading Doses)
While meropenem does not require a loading dose, extended infusion over 3 hours is recommended for specific situations to optimize pharmacodynamic targets:
For carbapenem-resistant Enterobacteriaceae (CRE): 1 gram IV every 8 hours by extended 3-hour infusion 2, 4
When MIC ≥8 mg/L: Extended 3-hour infusion is suggested to maintain adequate drug levels above the MIC 1, 2, 3
For high MIC organisms (≥16 mg/L): Consider 2 grams IV every 8 hours with 3-hour prolonged infusion 2
Contrast With Other Antibiotics
This differs markedly from other antimicrobials used in similar clinical contexts:
Colistin requires a loading dose: 5 mg CBA/kg IV loading dose before maintenance dosing 1
Tigecycline requires a loading dose: 100 mg IV loading dose before 50 mg every 12 hours 1
Vancomycin benefits from loading doses: 35 mg/kg loading dose recommended for rapid target attainment 1
Clinical Rationale
The pharmacokinetic profile of meropenem explains why no loading dose is needed:
Peak plasma concentrations of approximately 30 mg/L are achieved rapidly after standard dosing 5
The elimination half-life is approximately 1 hour in patients with normal renal function 5
Therapeutic levels are reached quickly with standard intermittent dosing 6
The key to meropenem optimization is not a loading dose, but rather ensuring adequate time above MIC through extended infusion when treating resistant organisms or critically ill patients. 1, 2