Pharmacokinetics of Piperacillin and Tazobactam in Critically Ill Patients

Optimal understanding of piperacillin-tazobactam pharmacokinetics in critically ill patients is lacking resulting in large variation of achieved exposure and possible inadequate therapy. The investigators hypothesize that drug dosing based on CKD-EPIcr-cys provides a useful method to individualize and optimize therapy for piperacillin-tazobactam and eventually improve outcome. In a multi-centre, observational, open-label study the investigators aim to define PK of free drug concentrations of both piperacillin and tazobactam in ICU patients and define a PK model for estimation of renal function that most accurately predicts piperacillin and tazobactam clearance.