Nineteen bears, representing five species (Helarctos malayanus, Ursus americanus, Ursus arctos, Tremarctos ornatus, Melursus ursinus) were immobilized a total of 52 times using either phencyclidine-promazine or tiletamine-zolazepam. Blood gas, hematology, and serum biochemistry values were determined during the immobilizations.

Immobilizations conducted with tiletamine-zolazepam were characterized by rapid induction and recovery times, good muscle relaxation, and relative freedom from convulsions. Bears immobilized with phencyclidine-promazine had longer induction and recovery times and showed convulsive activity in 29% of the trials with that combination.