title: A multicentre, prospective, randomised, blinded clinical trial to compare some perioperative effects of buprenorphine or butorphanol premedication before equine elective general anaesthesia and surgery.
abstract: BACKGROUND
  Buprenorphine, a μ-agonist opioid, has recently been licensed for equine use, but butorphanol, a κ-agonist opioid, is more commonly used in horses. The effect of the 2 opioids has not previously been compared in a large clinical study.
  
  
  OBJECTIVE
  To compare post operative analgesia and physiological variables in horses undergoing elective surgery following premedication with either buprenorphine or butorphanol in a conventional clinical setting.
  
  
  METHODS
  Multicentre, prospective, randomised, blinded clinical investigation.
  
  
  METHODS
  Eighty-nine healthy horses admitted for elective surgery to one of 6 UK equine veterinary clinics were premedicated with acepromazine, a nonsteroidal anti-inflammatory drug, and romifidine followed by intravenous (i.v.) buprenorphine or butorphanol. Anaesthesia was induced with diazepam/ketamine and maintained with isoflurane in oxygen. A range of surgical procedures were performed and supplementary anaesthetic agents given as required. Physiological variables were monitored during anaesthesia and pain, ataxia, sedation and vital function were assessed post operatively. Data were analysed using t-tests, ANOVA, Mann-Whitney U-test and Chi-squared test as appropriate and P<0.05 was regarded as significant, except for multiple comparisons, when P<0.01 was used.
  
  
  RESULTS
  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 1 h of ceasing anaesthesia. There were no significant differences between groups in any variable except post operative pain when scores (simple descriptive scale) between 3 and 6 h were significantly lower after buprenorphine than after butorphanol.
  
  
  CONCLUSIONS
  Horses experienced less post operative pain after buprenorphine than after butorphanol premedication. Compared with butorphanol, buprenorphine did not cause any different effects on vital function.
authors.affiliation: Taylor Monroe, Little Downham, Cambridgeshire, UK.
authors.forename: P M
authors.initials: PM
authors.lastname: Taylor
authors.affiliation: School of Veterinary Medicine and Science, Nottingham University, Sutton Bonington, Leicestershire, UK.
authors.forename: H R
authors.initials: HR
authors.lastname: Hoare
authors.affiliation: Animal Health Trust, Newmarket, Suffolk, UK.
authors.forename: A
authors.initials: A
authors.lastname: de Vries
authors.affiliation: Equine First Opinion and Referral Clinic, University of Bristol, Langford, Bristol, UK.
authors.forename: E J
authors.initials: EJ
authors.lastname: Love
authors.affiliation: Bell Equine Clinic, Mereworth, Kent, UK.
authors.forename: K M
authors.initials: KM
authors.lastname: Coumbe
authors.affiliation: School of Veterinary Medicine and Science, Nottingham University, Sutton Bonington, Leicestershire, UK.
authors.forename: K L
authors.initials: KL
authors.lastname: White
authors.affiliation: School of Veterinary Science, University of Bristol, Langford, Bristol, UK.
authors.forename: J C
authors.initials: JC
authors.lastname: Murrell
mesh_terms: D000768:Anesthesia, General / Q000662:veterinary*; D018685:Anesthetics, Inhalation; D000818:Animals; D002047:Buprenorphine / Q000008:administration & dosage / Q000494:pharmacology*; D002077:Butorphanol / Q000008:administration & dosage / Q000494:pharmacology*; D006734:Horse Diseases / Q000601:surgery*; D006736:Horses; D059035:Perioperative Period / Q000662:veterinary*; D011292:Premedication / Q000662:veterinary*; D013514:Surgical Procedures, Operative / Q000662:veterinary
chemical_list: D018685:Anesthetics, Inhalation; D002047:Buprenorphine; D002077:Butorphanol
keywords: buprenorphine; butorphanol; general anaesthesia; horse; opioid