Piperacillin Pharmacokinetics in ICU Patients

Antibiotic dosing in critically ill patients poses a challenge for clinicians due to the pharmacokinetic changes seen in this population. Piperacillin/tazobactam is often used for empirical treatment, and initial appropriate dosing is crucial for reducing mortality. Patients in the Intensive Care Unit (ICU), treated with piperacillin/tazobactam, had their plasma concentration of piperacillin determined 1-3 times weekly. Patients received piperacillin as intermittent bolus infusion 3 times daily or as continuous infusion (this was up to the treating physician). Time above the minimal inhibitory concentration (T\>MIC) estimated for each patient was evaluated against clinical breakpoint MIC for Pseudomonas aeruginosa (16 mg/L). Pharmacokinetic-pharmacodynamic (PK-PD) targets evaluated were 100% f T\>MIC (free piperacillin concentration maintained above the MIC throughout the dosing interval) and 50% fT\>4xMIC (free piperacillin concentration maintained at a level fourfold the MIC for at least 50% of the dosing interval).