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Adverse effects of gentamicin in scarlet macaws and galahs
K Flammer1, C H Clark, L A Drewes
1Department of Companion Animal and Special Species Medicine, College of Veterinary Medicine, North Carolina State University, Raleigh 27606.
Abstract:
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 less than 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) micrograms/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 less than 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.
Insights
Gentamicin administration in macaws and cockatoos caused increased thirst and urination, with effects lasting longer in cockatoos. Liver enzymes also showed changes in both species after treatment.
Area of Science:
- Avian medicine
- Veterinary pharmacology
- Toxicology
Background:
- Gentamicin is a widely used antibiotic in avian species.
- Understanding its adverse effects in psittacines is crucial for safe clinical application.
- Scarlet macaws (Ara macao) and galahs (Eolophus roseicapillus) were selected for this study.
Purpose of the Study:
- To evaluate the adverse effects of gentamicin administration in scarlet macaws and galahs.
- To assess physiological and biochemical changes following gentamicin treatment.
- To determine plasma gentamicin concentrations and elimination half-life in these avian species.
Main Methods:
- Healthy scarlet macaws and galahs were administered gentamicin (5 mg/kg) intramuscularly every 12 hours for 7 days.
- Polydipsia, polyuria, and water intake were monitored.
- Plasma aspartate transaminase (AST) and lactate dehydrogenase (LDH) activities were measured.
- Plasma gentamicin concentrations and elimination half-lives were determined.
Main Results:
- Polydipsia and polyuria were observed in both species, more pronounced and prolonged in galahs.
- Peak water intake in galahs increased over fourfold and remained elevated for 23 days post-treatment.
- Significant increases in plasma AST were noted in macaws, and both AST and LDH increased in galahs.
- Plasma gentamicin concentrations were similar between species, except at 12 hours where galahs had higher levels.
- Elimination half-lives ranged from 1.07 to 1.44 hours, with no significant species difference.
Conclusions:
- Gentamicin administration can induce significant polydipsia, polyuria, and biochemical changes in macaws and galahs.
- Galahs exhibit a more pronounced and persistent response to gentamicin-induced diuresis.
- Further research is needed to correlate drug disposition with observed adverse effects.