Comparative study of the effects of medetomidine and xylazine in cats

RESUMO

The objectives of this study were to compare the clinical effects and glycemia induced by medetomidine and xylazine in healthy cats and to demonstrate the reversal of the effects by atipamezole. A prospective blinded randomized experimental trial was used with twenty-four healthy adult cats. The animals were allocated into 4 groups of 6 animals each to receive by intramuscular route (IM) Group M (medetomidine - 50 g/ kg); Group X (xylazine - 1.1 mg/kg); Group MA (medetomidine - 50 g/kg and 60 minutes later atipamezole - 0.2 mg/kg); Group XA (xylazine - 1.1 mg/kg and 60 minutes later atipamezole - 0.2 mg/kg). Rectal temperature, respiratory rate, heart rate, systolic arterial pressure, electrocardiogram, intraocular pressure, degree of sedation were measured at 0, 30, 60, 120 and 180 minutes, and the serum glucose concentration was measured at 0, 60, 120 and 180 minutes. The xylazine at a dose of 1.1 mg/kg and medetomidine at a dose of 50 g/kg (both intramuscular) induced hypothermia, decreased heart rate, respiration and blood pressure and also 1st-degree A-V block in some cats, but it did not interfere significantly with intraocular pressure. The medetomidine induced a more pronounced hypothermia, sedation and hyperglycemia than xylazine in cats. The atipamezole was an excellent antagonist of the effects induced by medetomidine and xylazine in cats. Also, it did not interf