O-2 Population and developmental pharmacokinetic analysis to evaluate and optimise cefotaxime dosing regimen in neonates and young infants

Abstract

Background Cefotaxime is one of the most frequently prescribed antibiotics for the treatment of Gram-negative bacterial sepsis in neonates. However, the dosing regi-mens routinely used in clinical practice vary considerably. The objective of the present study was to conduct a population pharmacokinetic study of cefotaxime in neonates and young infants in order to evaluate and optimise the dosing regimen. Methods An opportunistic sampling strategy com-bined with population pharmacokinetic analysis using NONMEM software was performed. Cefotaxime concentrations were measured by high-performance liquid chromatography tandem mass spectrometry. Developmental pharmacokinetics-pharmacodynamics, the microbiological pathogens, and safety aspects were taken into account to optimise the dose. Results The pharmacokinetic data from 100 neonates (gestational age [GA] range, 23 to 42 weeks) were modeled with an allometric two compartment model with first-order elimination. The median values for clearance and volume of distribution at steady state were 0.12 litre/h/kg of body weight and 0.64 litre/kg, respectively. The covariate analysis showed that current weight, GA, and postnatal age [PNA] had significant impacts on ce-fotaxime pharmacokinetics. Monte Carlo simulations demonstrated that the current dose recommendations underdosed the older newborns. A model-based dosing regimen of 50 mg/kg twice a day to four times a day, according to GA and PNA, was established. The associated risk of overdose for the proposed dosing regimen was 0.01%. Conclusion We determined the population pharma cokinetics of cefotaxime and established a model based dosing regimen to optimise treatment for neonates and young infants.