Clinical pharmacology of amikacin and kanamycin.

During and after a 4-hr intravenous infusion of amikacin and kanamycin in a cross-over study in healthy adult male volunteers, average concentrations of drug in serum were similar, with half-lives of approximately 2 hr. Apparent volumes of distribution at the steady state averaged 30% of body weight, and the rate of renal clearance was less than the rate of creatinine clearance (83 vs. 120 ml/min), a finding that indicates tubular reabsorption. The rate of serum clearance was greater than the rate of renal clearance (100 vs 83 ml/min). Urinary excretion in 24 hr averaged 94% of the dose, and there was no binding of serum proteins. In another cross-over study, volunteers received single intramuscular injections of these antibiotics. Peak concentrations of drug in serum after 45 min to 2 hr averaged 19.9 and 19.0 mug/ml for amikacin and kanamycin, respectively. Serum half-lives between 4 and 8 hr after administration of drug were 2 hr, and an average of 94% of the dose was recovered in the urine in 24 hr. Thus, the pharmacologic properties of amikacin and kanamycin were virtually identical.