Population Pharmacokinetics and Dose Optimization of Piperacillin in Infants and Children with Pneumonia.

We aimed to determine the piperacillin disposition and optimize the dosing regimens for infants and children with pneumonia. An opportunistic sampling strategy was used in this pharmacokinetic study. High-performance liquid chromatography was used to measure the concentrations of piperacillin in plasma samples. A population pharmacokinetic model was conducted using NONMEM. The pharmacokinetic data of 90 samples from 64 infants and children with pneumonia (age range: 0.09–1.72 years for infants and 2.12–11.10 years for children) were available. A two-compartment model with first-order elimination was the most suitable model to describe the population pharmacokinetics of piperacillin. A covariate analysis indicated that body weight and age were significant factors affecting clearance. Monte Carlo simulations showed that a 50-mg/kg every 8 h or every 12 h dosing regimen results in underdosing. Results both in infants and children showed that an extended infusion (3 h) of various dosing regimens (80, 100, or 130 mg/kg) three times daily or a 300-mg/kg continuous infusion can reach a therapeutic level based on the chosen target for the probability of target attainment threshold of 70