This study compared the anesthetic and cardiorespiratory effects of 3 intramuscular anesthetic combinations in 8 dogs. Tiletamine-zolazepam (8 mg kg^-1) and xylazine (0.5 mg kg^-1) (TZX); Tiletamine-zolazepam (8 mg kg^-1), xylazine (0.5 mg kg^-1) and tramadol (2 mg kg^-1) (TZXT); or the TZXT protocol plus atipamezole (0.05 mg kg^-1) given 30 min later to reverse xylazine, were administered. Immobilization and analgesia scores of the dogs and baseline physiological parameters (heart rate, respiratory rate, non-invasive systolic, diastolic and mean arterial blood pressures, arterial hemoglobin oxygen saturation, and rectal temperature) were determined. All 3 combinations effectively induced anesthesia, and dogs became laterally recumbent within 5 min. The changes in physiological parameters after administration of the drug combinations remained within biologically acceptable limits. While both TZX and TZXT appeared to be effective injectable anesthetic combinations, TZXT provided significantly better analgesia with a longer duration than did TZX. Atipamezole administration provided effective antagonism and no adverse effects were observed in this study.

Key words: Atipamezole, Canine, Physiological parameters, Tiletamine/zolazepam, Tramadol, Xylazine