Comparison of the Anesthetic Effects of Oral versus Injectable Medetomidine in Combination with Tiletamine-Zolazepam for Immobilization of Chimpanzees (Pan troglodytes)
Seventeen adult chimpanzees (Pan troglodytes) with an average age of 37 years were immobilized with a combination of tiletamine-zolazepam (TZ) and medetomidine (MED) in one of two modes of delivery. Group A animals received the drug combination intramuscularly at 3 mg/kg and 0.05 mg/kg, respectively. Animals in Group B received 0.1 mg/kg of medetomidine orally, mixed with marshmallow crème, followed by 3 mg/kg of TZ intramuscularly. All chimpanzees were compliant with oral transmucosal drug administration, although two chimpanzees preferred oral MED mixed with applesauce. All animals exhibited some anxiety and excitatory behavior associated with darting, but this was reduced in Group B which was premedicated with oral transmucosal MED. The mean time from TZ administration to sedation sufficient for human contact was 16.4 and 14.7 minutes with and without oral transmucosal premedication, respectively. The mean time for recovery for those chimpanzees offered oral transmucosal premedication was 13.8 minutes, which was significantly shorter than the time of recovery for the group not offered oral premedication. Oral transmucosal administration of MED provided a light sedation in 16/17 chimpanzees to the level of arousable recumbency and a heavier sedation in one chimpanzee with no adverse side effects. TZ combined with MED by either oral transmucosal or injectable administration provided safe, heavy, long sedation with rapid, smooth, uneventful recoveries.
The authors would like to thank veterinary technician Jennifer Best and the Chimp Haven staff for their support and assistance in this study, statistician Dr. Richard Evans, and Chicago Zoological Society, Brookfield Zoo for their support.