Prolonged Beta-lactam Antibiotic Infusion in the Treatment of Sepsis in ICU

Beta-lactams are a category of antibiotics that are most effective when their plasma concentrations persistently exceed the minimum inhibitory concentration (MIC) , thus classifying them as time-dependent antibiotics. In this context, the critical pharmacodynamic parameter simplifies to the time period where serum concentrations surpass the MIC within the dosing interval, labeled as t above MIC.
Standard intermittent infusions, administered over 30-60 minutes, lead to fluctuating drug concentrations with characteristic peaks and troughs. Conversely, prolonged infusions, either extended over 2-4 hours or given continuously, may deliver more stable serum levels that consistently exceed the minimum inhibitory concentration required for the targeted pathogen.
Prolonged infusions are particularly beneficial when addressing infections from gram-negative organisms with higher susceptibility-range MICs, and in critically ill patients, where pharmacokinetics are frequently variable due to changes in drug clearance and distribution, fluid balance, and protein binding.
In the following discourse, we will meticulously examine the existing body of evidence on this topic, specifically focusing on the findings from the recently published MERCY trial.