Comparison of the effects of atipamezole and tolazoline on analgesia, cardiopulmonary and rectal temperature changes induced by lumbosacral epidural injection of medetomidine in goats
Mpanduji, D.G|Bitegeko, S.B.P|Batumuzi, E.K|Mgasa, M.N|Shami, C.L / 2000

The present study was carried out in order to compare the reversing effects of a2-adrenergic receptor blockers, atipamezole and tolazoline on analgesia, cardiopulmonary depression and rectal temperature changes induced by epidural administration of medetomidine in goats. Eight clinically healthy, Small East African goats of both sexes weighing between 12 to 17kg (mean 14.4±1.8kg) were used in this study. The animals were randomly divided into two groups of four animals. The first group was given 20mg/kg medetomidine followed by intravenous (IV) administration of 80mg/kg atipamezole, 30 minutes after the initial injection. The second group was given same treatment of medetomidine as group one but followed by IV administration of 2.2mg/kg tolazoline, 30 minutes after the initial injection. In both treatment groups, medetomidine was administered epidurally through the lumbosacral intersperse. Analgesia of the flank and perineum was evaluated at 10 minutes intervals up to 60 minutes. The cardiopulmonary and rectal temperature values were monitored and recorded after every 5 minutes up to 60 minutes. In both groups, lumbosacral epidural injection of medetomidine induced generalised analgesia, variable cardiopulmonary and rectal temperature depression. These changes developed as early as five minutes and continued until when a2 /a1 blockers were administered. Intravenous administration of a-adrenergic receptor blockers; atipamezole and tolazoline reversed the analgesia, cardiopulmonary and rectal temperature changes induced by lumbosacral epidural injection of medetomidine. However, atipamezole appeared to be superior (P<0.05) to tolazoline. It was concluded that IV administration of 80mg/kg atipamezole was better than 2.2mg/kg tolazoline in reversing analgesia, cardiopulmonary depression effects and rectal temperature changes induced by lumbosacral epidural injection of medetomidine. This indicates the superiority of atipamezole to tolazoline as an antidote for medetomidine induced effects in goats.