The use of ketamine-xylazine and ketamine-medetomidine with and without their antagonists, yohimbine and atipamezole hydrochloride to immobilize Raccoons (Procyon lotor) in Ontario, Canada


  • Mike R. Allan Ontario Ministry of Natural Resources and Forestry, Wildlife Research and Monitoring Section, Trent University, DNA Building, 2140 East Bank Drive, Peterborough, Ontario K9J 7B8



ketamine, medetomidine, xylazine, yohimbine, atipamezole, raccoon, Procyon lotor, chemical immobilization


This study was undertaken to identify a drug combination that provided a suitable plane of anesthesia and pain suppression and reduced recovery time for minor surgical procedures in raccoons. In fall 2004, 40 wild Raccoons (Procyon lotor) were chemically immobilized using ketamine hydrochloride combined with either xylazine or medetomidine hydrochloride. Immobilizing treatments within and between drug types were compared in terms of induction, arousal and recovery times. The ketamine-xylazine (KX) group (n = 20) was given a combination of 20 mg/kg ketamine hydrochloride and 2 mg/kg xylazine hydrochloride by body weight, and the effects on induction, arousal and recovery time were recorded with and without the antagonist yohimbine hydrochloride. The ketamine-medetomidine (KM) group (n = 20) was given a combination of 5 mg/kg ketamine hydrochloride and 0.05 mg/kg medetomidine hydrochloride by body weight, and induction, arousal and recovery times were recorded with and without the use of the antagonist atipamezole hydrochloride. Administration of yohimbine hydrochloride at 0.1 mg/kg body weight to the KX group and atipamezole hydrochloride at 0.25 mg/kg body weight to the KM group produced considerably shorter arousal and recovery times in the KM group (P = 0.016). Mean arousal and recovery time with standard deviations ± ( SD ) for the KX group with yohimbine hydrochloride antagonist were 36.10 ± 10.69 and 94.2 ± 23.18 minutes; for the KM group with atipamezole hydrochloride antagonist, they were 7.95 ± 3.94 and 65.58 ± 14.75 respectively. At these doses, the KM combination reversed with atipamezole hydrochloride significantly reduced arousal and recovery times and resulted in a quality of anesthesia that would allow safe tooth and blood extraction in Raccoons.