Medetomidine- and medetomidine-ketamine-induced immobilization in blue foxes (Alopex lagopus) and its reversal by atipamezole.

The sedative and immobilizing effects of the alpha 2-adrenoceptor agonist medetomidine alone or combined with the dissociative anesthetic ketamine, were studied in blue foxes. Medetomidine at doses of 25 and 50 micrograms/kg induced moderate to deep sedation, but only with the highest medetomidine dose tested, 100 micrograms/kg, was the immobilization complete. Medetomidine 50 micrograms/kg combined with ketamine 2.5 mg/kg rapidly induced complete immobilization, characterized by good myorelaxation, and no clinically significant alterations in serially determined hematologic and serum chemistry parameters. The alpha 2-adrenoceptor antagonist atipamezole effectively reversed the medetomidine- or medetomidine-ketamine-induced immobilizations. A transient increase in heart rates was noted after each atipamezole injection.