Meropenem Dosing in Renal Impairment

Pharmacokinetic/Pharmacodynamic Considerations

For beta-lactams like meropenem, the key pharmacodynamic parameter for clinical efficacy is the time that plasma concentration remains above the pathogen's minimum inhibitory concentration (T>MIC) 1, 2
A minimum T>MIC of 60% is generally sufficient for mild to moderate infections, but optimal response in severe infections like sepsis requires T>MIC approaching 100% 2, 3
More frequent dosing (every 8 hours vs every 12 hours) with the same total daily dose provides better T>MIC coverage 2

Sepsis requires optimal antimicrobial dosing strategies due to altered pharmacokinetics including increased volume of distribution 1, 4
The Surviving Sepsis Campaign guidelines emphasize optimizing antimicrobial dosing based on pharmacokinetic/pharmacodynamic principles 3, 4
For critically ill patients, maintaining consistent antimicrobial levels is crucial for effective treatment 3

Loading doses are not affected by renal function and should be administered at full dose to rapidly achieve therapeutic levels 2, 3

Assuming that less frequent dosing is always better in renal impairment ignores the importance of maintaining T>MIC 2
Failing to consider that sepsis itself alters drug pharmacokinetics beyond what would be expected from renal impairment alone 1, 4