Vancomycin individual dosing regimens via Bayesian simulation: a 5-year retrospective study on preterm and term neonates.

Aim: Vancomycin dosing in neonates is challenging due to developmental pharmacokinetic variability. The study was to characterize vancomycin pharmacokinetics in a large cohort of preterm and term neonates and develop individualized dosing regimens.

Materials & methods: A 5-year retrospective study of a cohort of 255 neonates was included.

Results: An allometric one-compartment model with first-order elimination best described the vancomycin concentrations. The population pharmacokinetic estimates (between subject variability) of clearance (CL) and volume of distribution (V) were 2.58 L·h^-1·70 kg^-1 (9.00 %) and 52.09 L·70 kg^-1 (29.00%), respectively. CL and V were significantly influenced by body weight and postmenstrual age. Vancomycin CL reached 50% of adult values at 43.6 weeks PMA (a sigmoid Emax model). Renal maturation, estimated by creatinine production rate, was a significant covariate. Bayesian-guided individualized dosage regimens were developed and evaluated.

Conclusions: Vancomycin overdosage should be avoided in very young premature babies (PMA = 25 weeks). Optimization of efficacy while minimizing toxicity of vancomycin in preterm and term neonates is needed, especially guided by personalized body weight, postmenstrual age, and renal function.