Evaluation of amikacin dosage regimes in the low and very low birthweight newborn.

The recommended neonatal dosage regime for amikacin of 15 mg/kg/day was found to be unsatisfactory in four neonates and a loading dose of 10 mg/kg did not improve levels in two further newborns with normal renal function. Fourteen neonates on 20 mg/kg/day regime achieved satisfactory levels; peak values were 21.5 +/- 4.5 microgram/ml and trough levels 3.34 +/- 2.05 microgram/ml. Peak time ranged from 17 to 60 minutes and varied with the dose given. The half-life was related to plasma creatinine, urea, post-natal age and weight. Thirteen neonates with pre-existing renal impairment were managed by alteration of dosage interval or quantity given. Side-effects were confined to eosinophilia in six infants, and no definite nephrotoxicity or gross eighth nerve damage was demonstrated.