Population pharmacokinetics of amikacin in Korean neonates

Population pharmacokinetics of amikacin were analyzed from 287 concentrations obtained from 141 Korean newborn patients with a postconceptional age(PCA) ranging between 26.4 weeks and 45 weeks undergoing therapeutic drug monitoring of their amikacin levels. Population parameters were estimated from fitting concentration data to a single compartment model using program NONMEM. Body weight was a good predictive variable for both clearance (CI) and volume of distribution(Vd), and the best fitting of clearance was obtained when subjects were classified to three subgroups according to PCA. Five minutes Apgar score also seemed to influence on the prediction of clearance. Mean population pharmacokinetic value of Vd was 0.57 L/kg. Clearance was 0.099 L/kg/h and was reduced in neonates with PCA<33weeks(× 0.74), 33weeks ≤ PCA<37weeks(× 0.57), and 5 minutes Apgar score < 8(×0.9). These population mean parameters were used to generate dosage regimen to achieve concentrations within the therapeutic range in Korean neonates.