Research from the United Kingdom was recently published on Wiley.com from the Equine Veterinary Journal. The article was titled, “A multicentre, prospective, randomised, blinded clinical trial to compare some perioperative effects of buprenorphine or butorphanol premedication before equine elective general anaesthesia and surgery.” You can rent or purchase the article online.
Reasons for Performing Study
Buprenorphine, a mu-agonist opioid has recently been licensed for equine use but butorphanol, a kappa-agonist opioid, is more commonly used in horses. The effect of the 2 opioids has not been compared in a large clinical study.
To compare postoperative analgesia and physiological variables in horses undergoing elective surgery following premedication with either buprenorphine or butorphanol in a conventional clinical setting.
Multicentre, prospective, randomised, blinded clinical investigation.
Healthy horses (89) admitted for elective surgery to one of 6 UK equine veterinary clinics were premedicated with acepromazine, a non-steroidal anti-inflammatory drug and romifidine followed by intravenous buprenorphine (5-10 μg/kg) or butorphanol (0.02-0.1 mg/kg). Anaesthesia was induced with diazepam/ketamine and maintained with isoflurane in oxygen. A range of surgical procedures were performed. Supplementary anaesthetic agents were given as required. Physiological variables were monitored during anaesthesia, and pain, ataxia, sedation and vital function were assessed postoperatively. Data were analysed using t-tests, ANOVA, Mann Whitney U and Chi squared tests as appropriate. P<0.05 was regarded as significant except for multiple comparisons when P<0.01 was used.
Surgery was carried out successfully in all cases and no mortality or serious morbidity occurred. Physiological variables remained within normal limits and all horses recovered successfully, most standing within one hour of ceasing anaesthesia. There were no significant differences between groups in any variable except postoperative pain when scores (simple descriptive scale) between 3 and 6 h were significantly lower after buprenorphine than butorphanol (3 h P<0.001; 4 h P<0.001; 5 h P<0.002).
Horses experienced less postoperative pain after buprenorphine than butorphanol premedication. Compared with butorphanol, buprenorphine did not cause any different effects on vital function.
P.M. Taylor, Taylor Monroe, Gravel Head Farm, Little Downham, Ely, Cambridgeshire, UK; H.R. Hoare, School of Veterinary Medicine and Science, Nottingham University, Sutton Bonington, Leicestershire, UK; A. de Vries, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, UK; E. J. Love, Equine First Opinion and Referral Clinic, Langford House, University of Bristol, Langford, Bristol, UK; K. M. Coumbe, Bell Equine Clinic, Butchers Lane, Mereworth, Maidstone, Kent, UK; K. L. White, School of Veterinary Medicine and Science, Nottingham University, Sutton Bonington, Leicestershire, UK; and J.C. Murrell, School of Veterinary Science, Langford House, University of Bristol, Langford, Bristol, UK.