Gentamicin dosing in the newborn. Use of a one-compartment open pharmacokinetic model to individualize dosing

Gentamicin 2.5 mg/kg was given to 60 term and preterm neonates. Serum gentamicin concentrations were determined at 1, 7 and 11 h postinfusion. Linear regression analysis was used to determine half-life and volume of distribution. From these data a new dosing regimen and a predicted steady-state peak and trough gentamicin concentration were determined for each neonate. The predicted peak and trough were compared to a measured peak or trough drawn at least 48 h later. Criteria for successful peaks were met in 93% of the patients, while criteria for successful troughs were met in 83%. Individualized gentamicin dosing in the newborn based on a one-compartment open pharmacokinetic model is a useful clinical tool in predicting peak and trough gentamicin concentrations.