Population Pharmacokinetic Study of Prophylactic Fluconazole in Preterm Infants for Prevention of Invasive Candidiasis

Fluconazole is an antifungal agent with reported evidence for its prophylactic effect against systemic fungal infection in preterm infants. The aim of this study was to build a population pharmacokinetic model to evaluate the pharmacokinetic characteristics of intravenous and oral fluconazole in preterm infants with the current prophylactic fluconazole dosing regimen. A pharmacokinetic model was developed using 301 fluconazole concentrations from 75 preterm infants with a baseline body weight (WT) ranging from 0.5 to 1.5 kg and an estimated glomerular filtration rate (eGFR) ranging from 12.9 to 58.5 ml/min/1.73 m(2). Eligible infants received an intravenous or oral dose of 3 mg/kg of body weight of fluconazole, twice weekly with a >= 72-h dose interval, for 4 weeks. The model was qualified with basic goodness-of-fit diagnostics, visual predictive checks, and bootstrapping. The fluconazole pharmacokinetics was well described with a one-compartment linear model with a proportional residual error. The population clearance (CL) and volume of distribution (V) were derived as 0.0197 x (WT/1.00)(0.746) x (eGFR/25.0)(0.463) x exp(eta) and 1.04 x WT x exp(eta), respectively. Such covariate analyses augment the awareness of the need for personalized dosing in preterm infants.