Pharmacology of Kanamycm in the Newborn

The authors studied the pharmacologic effects of kanamycin in these groups of newborn infants: group 1-birth weight (BW) ≤ 2,000 gm, chronologic age (CA) < 7 days; group 2-BW > 2,000 gm, CA < 7 days; and group 3 - BW > 2,000 gm, CA 7 to 28 days. The dose of kanamycin was 15 mg/kg/day, administered in two intramuscular doses. Serum kanamycin levels were measured 15 minutes before the dose and 1/2 , 1, 6 and 8 hours after the dose. Infants in group 1 had a mean peak concentration of 18.7 μg/ml, those in group 2, 19.6 μg/ml, and those in group 3, 15.6 μg/ml. The mean peak concentrations varied inversely with chronologic age but were not influenced by birth weight. Mean serum half-life varied inversely with birth weight, gestational age, and chronologic age. The authors recommend a standard dose of 15 mg/kg/day for newborn infants. Modification of this dose may be required for individual infants.