Short CommunicationOptimizing beta-lactam pharmacodynamics against Pseudomonas aeruginosa in adult cystic fibrosis patients

BackgroundPatients with cystic fibrosis (CF) exhibit increased clearance of beta-lactams. The purpose of this study was to predict the probability of beta-lactam target attainment (PTA) against Pseudomonas aeruginosa in adult CF patients based on local microbiological data.MethodsCF-specific pharmacokinetic parameters were obtained from published data for aztreonam, cefepime, ceftazidime, meropenem and piperacillin-tazobactam. Pharmacodynamic modeling was used to determine the PTA for bolus, prolonged infusion, and continuous infusion regimens.ResultsProlonged infusion of meropenem 2 g every 8 h performed the best among all regimens tested, with a PTA of 83%. The PTA was increased with both prolonged and continuous infusion; however, no regimen reached the target PTA of > 90% against P. aeruginosa in CF patients at our institution.ConclusionsProlonged and continuous infusion provided higher PTA than bolus for all regimens. Further investigation of novel regimens in CF patients is needed.