A Comparative Study of Medetomidine‐Butotphanol‐Ketamine and Medetomidine‐Ketamine Anaesthesia in Dogs

The anaesthetic and cardiopulmonary effects of medetomidine (20 micrograms/kg)-butorphanol (0.1 mg/kg)-ketamine (MBK) (2.5, 5.0, 7.5 mg/kg) and medetomidine (40 micrograms/kg)-ketamine (5.0 mg/kg) (MK) were compared in dogs. The induction time (time from the initial injection of the sedative to lateral recumbency) by medetomidine-butorphanol (6.0 +/- 2.3 min) was significantly shorter than that by medetomidine alone (10.4 +/- 2.9 min). The duration of anaesthesia induced by MK was shorter than that by MBK2.5. The analgesic effects of MBK were more potent than those of MK. Mean arterial blood pressure increased significantly after administration of the sedatives, and then decreased to base-line value after the ketamine injection and remained stable throughout the experimental period. Respiratory rate decreased gradually after the administration of each sedative and was depressed until 60 min after the ketamine injection. MBK anaesthesia is effective and widely available for therapeutic procedures depending upon the selection of the ketamine dose.