The Veterinary Record, Vol 153, Issue 15, 462-465
Copyright © 2003 by British Veterinary Association

Changes in thermal threshold response in eight cats after administration of buprenorphine, butorphanol and morphine

¹ Department of Clinical Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES
² College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA

Thermal thresholds were measured in eight cats after the intramuscular administration of morphine (0·2 mg/kg), buprenorphine (0·01 mg/kg) or butorphanol (0·2 mg/kg), doses commonly used in clinical practice; 0·9 per cent saline (0·3 ml) was injected as a control. Groups of six cats were used and each cat participated in at least two treatments, according to a randomised design. The investigator was blinded to the treatments. The thermal thresholds were measured with a testing device developed specifically for cats, and measurements were made before and five, 30, 45 and 60 minutes and two, four, six, 12 and 24 hours after the injections. There was no significant change in thermal threshold after the injection of saline. With butorphanol, the threshold was increased only at five minutes after the injection and was decreased two hours after the injection; with morphine it was increased from between four and six hours after the injection, and with buprenorphine it was increased from between four and 12 hours after the injection.