Adverse effects of gentamicin in scarlet macaws and galahs

Abstract

SUMMARY The adverse effects of administration of gentamicin (5 mg/kg of body weight, im, q 12 h) for 7 days were studied in healthy scarlet macaws (Ara macao) and galahs (Eolophus roseicapillus; cockatoos). Polydipsia and polyuria developed in each species, but were greater and persisted longer in the cockatoos. Peak water intake in the cockatoos more than quadrupled, and remained increased for 23 days after cessation of gentamicin administration. Plasma aspartate transaminase activity increased significantly (P < 0.05) after treatment in the macaws, and plasma aspartate transaminase and lactate dehydrogenase activities increased in the cockatoos. Single im administration of gentamicin (5 mg/kg) resulted in mean (± sem) plasma concentration of 20.6 (± 1.85) μg/ml at 0.5 hour for either species of birds. There were no significant differences between mean plasma gentamicin concentrations for cockatoos and macaws at any time after drug administration, except at 12 hours, when values for cockatoos were significantly (P < 0.05) greater than those for macaws. The elimination half-life for gentamicin after im administration of 5 and 10 mg/kg was 1.17 and 1.07 hours, respectively, for macaws and 1.23 and 1.44 hours, respectively, for cockatoos. Correlation between drug disposition and adverse side effects could not be detected.