Carbapenems.

OBJECTIVE: To assess the relative strengths and weaknesses of carbapenems by considering their microbiological, clinical, pharmacokinetics and pharmacokinetic/pharmacodynamic (PK/PD) properties and defining optimal conditions of uses of the new generation of carbapenems.
METHODS: Literature review.
RESULTS: Except for ertapenem, the spectrum of activity is similar for all carbapenems, with little differences in activities of individual agents. The absence or reduced expression of two major porins in combination with various beta-lactamases and alteration of some penicillin binding proteins have been implicated in carbapenem resistance. All carbapenems are not alike, although they have very similar pharmacokinetic properties. The most important PK/PD parameter predicting bacteriological and clinical efficacy is T(>MIC). There is some circumstantial evidence, such as clinical data in severe critically ill septic patients, impaired renal function patients and neutropenic patients that imipenem has to exceed 66% of T(>MIC) to result in good clinical outcome. Continuous or extend infusion of carbapenems should result in at least equal efficacy to that of intermittent infusion in the treatment of infections with susceptible bacteria and appear highly appropriate for use in critically ill patients.
CONCLUSIONS: Maximizing clinical outcomes and minimizing antibiotic resistance using individualized doses may be best achieved with therapeutic drug monitoring of carbapenems.