Comparison of transdermal fentanyl and intramuscular oxymorphone on post-operative behaviour after ovariohysterectomy in dogs

The effects of transdermal fentanyl and IM oxymorphone on behavioural and p hysiological responses, after ovariohysterectomy in dogs, were investigated . The study involved three groups of 10 dogs: fentanyl/surgery (Fs), oxymor phone/surgery (OS), fentanyl/control (FC). A transdermal fentanyl delivery system (50 mu g hour(-1)) (FS and FC) was applied 20 hours before surgery, or IM oxymorphone (OS) was administered. After ovariohysterectomy (FS and O S) or anaesthesia alone (FC), dogs were continuously videotaped for 24 hour s and a standardised hourly interaction with a handler performed. The video tapes were analysed, and interactive and non-interactive behaviours evaluat ed. In addition, pain and sedation scores, pulse and respiratory rates, rec tal temperature, arterial blood pressure, plasma cortisol and plasma fentan yl concentrations were measured. This study showed that transdermal fentany l and IM oxymorphone (0.05 mg kg(-1)) produced comparable analgesic effects over a 24 hour recording period. LM oxymorphone produced significantly mor e sedation and lower rectal temperatures than transdermal fentanyl. There w ere no significant differences between groups in respiratory and heart rate s, and arterial blood pressures.