Evaluation of the Achievement of a Pharmacodynamic Target of Piperacillin‐Tazobactam for the Population With Obesity: An Open Randomized Controlled Feasibility Study (TAZO‐OBESITY Trial)

Background Observational studies report that prolonged infusions of piperacillin‐tazobactam may enable the achievement of an optimal clinically targeted free drug concentration above the minimum inhibitory concentration (fT > MIC). Objectives This study aimed to assess the feasibility of a randomized controlled trial (RCT) comparing standard to prolonged infusions of piperacillin‐tazobactam in the obese population. Methods In this open‐label RCT, patients with a body mass index (BMI) of 30 kg/m 2 or higher who initiated piperacillin‐tazobactam were recruited and randomly assigned to receive either standard or prolonged infusions of the antibiotic. Feasibility and safety outcomes were assessed. A blood sample was collected 24 h after the intervention to measure total piperacillin concentrations, with an exploratory aim of determining the proportion of patients who achieved 100% fT > MIC. Results A total of 45 patients were recruited at a rate of 7.2 patients per month with a consent rate of 42.1%, achieving these feasibility objectives. Adherence to blood sampling was 77.8%, below the 80% objective. On an exploratory basis, the proportion of patients who achieved 100% fT > MIC 24 h postintervention was 64.3% in the prolonged‐infusion group and 55.6% in the standard‐infusion group ( p = 0.725). There was no significant difference in the safety outcomes ( p = 0.756). Conclusion This first RCT evaluating prolonged infusions of piperacillin‐tazobactam in the obese population demonstrated the feasibility of the protocol. Although not statistically significant, the results suggest a favorable trend for fT > MIC attainment and no safety signal for prolonged infusions and support the conduct of a larger scale RCT. Trial Registration Clinical trial registration: NCT #06690905