Physiological effects of medetomidine-zolazepam-tiletamine immobilization in black bears

A combination of medetomidine-zolazepam-tiletamine (MZT) was used to immobilize four black bears (Ursus americanus). The drugs were used at a dose of approximately 52 micrograms/kg of medetomidine, 0.86 mg/kg of zolazepam, and 0.86 mg/kg of tiletamine. Induction occurred in 6.3 +/- 3.3 min (mean +/- SD). The combination produced minimal adverse cardiopulmonary effects. Hypertension occurred in all four bears. Oxygenation and ventilation was good in three of the four bears. One bear demonstrated slight hypoxemia and hypoventilation at 15 min following drug administration. At one 1 hr following drug administration atipamezole was administered at a dose of approximately 240 micrograms/kg. Recovery time was taken as the time from administration of the atipamezole until the time that the bear was sitting in the trap. Recovery occurred in 6.0 +/- 4.1 min. MZT produced rapid, reliable immobilization in black bears with minimal adverse physiological effects. Immobilization, produced by this combination, was readily reversible with atipamezole.