Sedative and Analgesic Effects of Medetomidine in Horses

Abstract

The sedative and analgesic effects of a new α₂ agonist medetomidine in horses were compared with those of xylazine. Five thoroughbred horses were treated on separate occasions with three intravenous doses of medetomidine (10μg/kg, 5μg/kg and 1μg/kg bodyweight) or with one intravenous dose of xylazine (1 mg/kg bodyweight) . Saline (5 ml/horse) was given intravenously as a negative control. Medetomidine at 10μg/kg produced severer and more prolonged sedative effect and ataxia than 1 mg/kg xylazine. Effects of medetomidine at 5μg/kg were similar to that of 1 mg/kg xylazine in duration of sedation less sedation and ataxia were produced. Medetomidine at 1μg/kg produced no sedation and no ataxia. An appropriate dosage of medetomidine for sedation was estimated as at 5μg/kg to 10 μg/kg. Medetomidine is a useful and economical sedative than xylazine in horses.