Medetomidine as a preanesthetic prior to ketamine-HCL and halothane anesthesia in laboratory beagles.

The potent sedative and analgesic effects of medetomidine confirm its potential use as a premedication to general anesthesia in dogs. In this study two different doses of medetomidine were tested as premedication to both ketamine HCl and halothane anesthesia in groups consisting of 4 laboratory beagles each. Cardiopulmonary parameters, anesthetic quality and dose requirements were recorded. Medetomidine was found to have favorable qualities in conjunction with these anesthetics. Atropine prevented the profound bradycardia and sinus arrhythmia seen with medetomidine alone. Cardiopulmonary parameters remained satisfactory in both groups, but no additional benefits could be seen from doses of 40 micrograms/kg medetomidine compared to 20 micrograms/kg, except a significant 30% reduction in halothane requirement. The positive chronotropic and inotropic properties of ketamine restored the medetomidine induced bradycardia and produced a short anesthetic period of 15-30 min depending on the dose of medetomidine. The quality of anesthesia was good in both groups, but recovery was quicker and smoother in the group with 20 micrograms/kg medetomidine.