Population kinetics of gentamicin in neonates.

A population kinetic analysis was carried out on sparse plasma gentamicin (GE) concentration data from 469 neonates obtained as part of a routine therapeutic drug monitoring (TDM) programme in the hospital neonatology unit. The best predictors of the kinetic parameters of the monoexponential model, volume of distribution (Vd) and clearance (CL), were the weight (WT) and gestational age (GA). Vd of the neonates was only related to WT, whereas the half-life was only related to the GA. The clinical implications of the findings are that the initial dose per WT administered to premature infants should be larger than that for term infants, because of a larger Vd per unit WT, and the intervals between maintenance doses should extended due to the prolonged half-life. Apart from these general guidelines, specific dose recommendations are also given.