The reversal of xylazine hydrochloride by yohimbine and 4-aminopyridine ingoats

Yohimbine, 4-aminopyridine, and a combination of the 2 drugs were studied t o assess their potential as antagonists to xylazine in goats. Twenty-four s mall East African goats were divided randomly into 4 groups of 6 goats each in a placebo-controlled study. They were all treated with intramuscular xy lazine at 0.44 mg/kg. At the time of maximum sedation, sterile water was ad ministered intravenously to the control group, 0.15% 4-aminopyridine at 0.4 mg/kg to Group 2, 0.1% yohimbine at 0.25 mg/kg to Group 3, and the combinat ion of the 2 drugs at the same dose rates to Group 4. The yohimbine/4-amino -pyridine combination was also used to antagonise xylazine at 0.88mg/kg in 6 goats. The heart rate, respiratory rate and rate of ruminal movements, th e pedal and palpehral reflexes as well as the reaction to noxious stimuli, the standing time and the total recovery time were established and evaluate d to assess the effects of the treatments. The drugs reversed the xylazine- induced decrease in the heart rate, respiratory rate and rate of ruminal mo vements, and also rapidly restored the reflexes as well as the reaction to noxious stimulation. In addition, they significantly (P < 0.05) decreased t he mean standing time. The mean total recovery time was decreased significa ntly (P < 0.05) by 4-aminopyridine and the yohimbine/4-aminopyridine combin ation, but non-significantly (P <greater than> 0.05) by yohimbine. No relap se in sedation occurred. Overall, the combination of yohimbine and 4-aminop yridine produced better responses than the individual drugs, and may theref ore be used for rapid reversal of xylazine-induced sedation in goats. Yohim bine or 4-aminopyridine may also be useful for this purpose but recovery ma y be prolonged.