Renal tubular enzyme effects of clarithromycin in comparison with gentamicin and placebo in volunteers.

This study assessed the potential nephrotoxicity of clarithromycin in comparison with gentamicin and placebo. Increased urinary excretion of alanine aminopeptidase (AAP) and N-acetyl-beta-D-glucosaminidase (NAG) served as markers of renal tubular injury. The study utilised a multiple-dose, double-blind, randomised, parallel group design. 14 healthy male subjects received 1 of 3 treatment regimens: (a) clarithromycin 500 mg orally every 12h for 13 doses and intravenous placebo every 8h (n = 5); (b) oral placebo every 12h and intravenous placebo every 8h (n = 4); and (c) intravenous gentamicin 1.7 mg/kg every 8h for 19 doses and oral placebo every 12h (n = 5). 24h urine collections were obtained daily for determinations of AAP and NAG activities. Gentamicin produced statistically significant increases (p less than 0.0001) in AAP and NAG excretion, with increases as early as the first and second day of dosing. Clarithromycin, when compared with placebo, did not produce significant elevations in AAP or NAG activity. On the basis of these data, it is unlikely that usual doses of clarithromycin have significant potential for causing nephrotoxicity.