Sedative and cardiorespiratory effects of medetomidine, medetomidine-butorphanol, and medetomidine-ketamine in dogs

Objective-To determine sedative and cardiorespiratory effects of IM adminis tration of medetomidine alone and in combination with butorphanol or ketami ne in dogs. Design-Randomized, crossover study. Animals-6 healthy adult dogs. Procedures-Dogs were given medetomidine alone (30 mu g/kg [13.6 mu g/lb] of body weight, IM), a combination of medetomidine (30 mu g/kg, IM) and butor phanol (0.2 mg/kg [0.09 mg/lb], IM), or a combination of medetomidine (30 m u g/kg, IM) and ketamine (3 mg/kg [1.36 mg/lb], IM), Treatments were admini stered in random order with a minimum of 1 week between treatments. Glycopy rrolate was given at the same time. Atipamezole (150 mu g/kg [68 mu g/lb], IM)was given 40 minutes after administration of medetomidine. Results-All but 1 dog (given medetomidine alone) assumed lateral recumbency within 6 minutes after drug administration. Endotracheal intubation was si gnificantly more difficult when dogs were given medetomidine alone than whe n given medetomidine and butorphanol. At all evaluation times, percentages of dogs with positive responses to tail clamping or to needle pricks in the cervical region, shoulder region, abdominal region, or hindquarters were n ot significantly different among drug treatments. The PaCO2 was significant ly higher and the arterial pH and PaO2 were significantly lower when dogs w ere given medetomidine and butorphanol or medetomidine and ketamine than wh en they were given medetomidine alone. Recovery quality following atipamezo le administration was unsatisfactory in 1 dog when given medetomidine and k etamine. Conclusions and Clinical Relevance-Results suggested that a combination of medetomidine with butorphanol or ketamine resulted in more reliable and uni form sedation in dogs than did medetomidine alone.