Comparative efficacy of yohimbine and tolazoline for antagonism of ketamine-xylazine induced sedation in captive wild felids

Abstract

This study was conducted to investigate the comparative efficacy of yohimbine and tolazoline for antagonism of ketamine-xylazine induced sedation in captive wild felids in Pakistan. It included 16 tigers (Panthera tigris), 22 lions (Panthera leo) and 16 leopards (Panthera pardus), aged between 2-10 years, weighing approximately 190.6±12.4 kg, 161.6±16.6 kg, and 50.5±6.9 kg respectively. A total of 54 anesthetic inductions were carried out on clinical patients from all species dividing them into two groups KX-T and KX-Y receiving 0.15 mg/kg tolazoline and 0.15 mg/ kg yohimbine as antagonists, respectively. Body temperature, pulse and respiration rate (TPR) were recorded at ten-minute intervals for thirty minutes in either groups. These physiological norms differed significantly only in Tigers at 10min and 20min intervals. Furthermore, onset of arousal and recovery time in animals receiving yohimbine was evidently shorter, ranging between 2.8±0.76 to 8.42±0.33 min. ALT, AST, Urea and Creatinine were significantly elevated in groups administered with Tolazoline when compared to Yohimbine as well. Hence, yohimbine at described dosage effectively antagonized ketamine and xylazine anesthesia by significant reduction in reversal times for all the species under consideration, bearing nominal deleterious effects on physiological, hepatic and renal parameters. So, this study concludes yohimbine to be a superior antagonist for ketamine-xylazine anesthetic reversal than tolazoline.