Comparative pharmacokinetics of amikacin and kanamycin

Abstract

Pharmacokinetic parameters of amikacin and kanamycin were compared in a crossover study using healthy adult male volunteers. Following an intravenous infusion of 3.33 mg per kilogram for 1 hour, an infusion of 1.00 mg per kilogram per hour over the next 3 hours produced a steady state with serum levels of approximately 12 mcg per milliliter. The apparent volumes of distribution were about 28% of total body weight, a relatively large value consistent with the observation that neither antibiotic is protein‐bound. Amikacin and kanamycin had serum half‐lives of about 2 hours, and renal clearance of the antibiotics (84 ml per minute) was less than the creatinine clearance (120 per milliliter per minute), indicating tubular reabsorption. Although 94% of the total dose was eventually recovered in the urine, clearance of the antibiotics from the serum was greater than renal clearance (100 versus 84 ml per minute), implying a small component of unidentified distribution or elimination. After single intramuscular injections of 7.5 mg per kilogram (about 0.6 gm), peak blood levels of about 18 mcg per milliliter were found, and the serum half‐life of each antibiotic was again about 2 hours. Thus the pharmacokinetic parameters of amikacin and kanamycin were Virtually identical.