Pharmacokinetics, sedative and behavioral effects of xylazine and detomidine, administered by different routes in Nordestino and Pêga breed donkeys (Equus asinus)

• Grant number: 11/24126-8
• Support Opportunities: Regular Research Grants
• Start date: March 01, 2012
• End date: August 31, 2014
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: Antonio José de Araujo Aguiar
• Grantee: Antonio José de Araujo Aguiar
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

The aims of this study are to evaluate the pharmacokinetics, sedative and behavioral effects of xylazine and detomidine administered intravenously and intramuscularly in Nordestino and Pêga breed donkeys. Twelve female asses will be used (six of each breed), in a three-phases study (previous study, I and II). The methodology of the previous study and Phase I will be similar, except for the pharmacokinetic analysis of Phase I, which results will be applied in the dose selection of both drugs for the Phase II. The sedative and behavioral effects will be evaluated in Phase I by changes in head height, ataxia degree and responses to auditive stimuli, and by measument of cardiorespiratory variables, as well as sampling of blood for analysis of plasma concentrations of xylazine and detomidine administered, to be performed later. In the Phase II, the cardiorespiratory effects, pharmacokinetics and the anestesia recovery effects of both ±2-agonists, administered by continuous intravenous infusion in the same donkeys submitted to isoflurane anestesia, will be evaluated. The infusion will be stopped after two hours of anestesia maintenance, and blood sampling will be continue during more 12 hours. Anesthesia recovery will be video-recorded for later analysis of its quality, to be performed by two investigators blinded to treatments. Plasma concentrations of xylazine and detomidine will be determined by HPLC and mass spectrometry. ANOVA and Tukey-Kramer test will be employed in the analysis of quantitative variables, and the Friedman's test with Dunn's multiple comparison will be used for non-parametric variables (p < 0.05). (AU)