Efeitos farmacodinâmicos de midazolam na associação com detomidina em equinos

Abstract

Sedative drugs are essential for performing diagnostic and surgical procedures in standing animals. In this context, assessing the sedative effect of different drugs and pharmacological combinations has been challenging for veterinary anesthesiologists. The objective of this study was to evaluate, from a double-blind in vivo crossover study, the sedative effect of the combination of detomidine and midazolam in horses. Four experimental protocols were performed: 15μg/kg of detomidine; association of detomidine (15μg/kg) with 25μg/kg (DM25), 50μg/kg (DM50), and 75μg/kg (DM75) of midazolam, administered intravenously. The sedative, myorelaxant effect, and animal physiological parameters were evaluated. Statistical analyzes were performed to compare the protocols, using a variance of bidirectional repeated measures (ANOVA) for parametric data, while for non-parametric data, the Friedman test was performed (significance P < 0.05). All protocols showed a decrease in head height, although there was no significant difference between them. The acoustic stimulus showed a statistical difference (P<0.05) at 10 minutes for the DM25 and DM50 protocols. Regarding myorelaxation, there was a statistical difference (P<0.05) for the effects of postural instability (DM75 time 10) and lingual relaxation (DM50 time 20). As for the physiological parameters, there was oscillation in the heart and respiratory rates; however, these remained within the normal range for the species. The decrease in gastrointestinal tract movements was evident, although there was no significant difference between the protocols. In this context, midazolam potentiated the myorelaxant effects (postural and lingual tonus) but not the sedative effects of detomidine. As a limitation of this work, the small sample size stands out, without racial variability, and the long-term effects were not investigated.