title: Comparison of perioperative analgesic efficacy between methadone and butorphanol in cats.
abstract: OBJECTIVE
  To compare the perioperative analgesic effect between methadone and butorphanol in cats.
  
  
  METHODS
  Randomized controlled clinical trial.
  
  
  METHODS
  22 healthy female domestic cats.
  
  
  METHODS
  Cats admitted for ovariohysterectomy were allocated to a butorphanol group (n = 10) or methadone group (12) and premedicated with butorphanol (0.4 mg/kg [0.18 mg/lb], SC) or methadone (0.6 mg/kg [0.27 mg/lb], SC), respectively, in combination with acepromazine (0.02 mg/kg [0.01 mg/lb], SC). Anesthesia was induced with propofol (IV) and maintained with isoflurane in oxygen. A multidimensional composite scale was used to conduct pain assessments prior to premedication and 5, 20, 60, 120, 180, 240, 300, and 360 minutes after extubation or until rescue analgesia was given. Groups were compared to evaluate isoflurane requirement, propofol requirement, pain scores, and requirement for rescue analgesia.
  
  
  RESULTS
  Propofol and isoflurane requirements and preoperative pain scores were not different between groups. During recovery, dysphoria prevented pain evaluation at 5 minutes. Pain scores at 20 minutes were significantly lower in the methadone group, and 6 of 10 cats in the butorphanol group received rescue analgesia, making subsequent pain score comparisons inapplicable. After 6 hours, only 3 of 12 cats in the methadone group had received rescue analgesia.
  
  
  CONCLUSIONS
  In the present study, methadone appeared to be a better postoperative analgesic than butorphanol and provided effective analgesia for 6 hours following ovariohysterectomy in most cats.
authors.affiliation: Faculty of Veterinary Science, The University of Melbourne, Werribee, VIC 3030 Australia.
authors.forename: Leon N
authors.initials: LN
authors.lastname: Warne
authors.forename: Thierry
authors.initials: T
authors.lastname: Beths
authors.forename: Merete
authors.initials: M
authors.lastname: Holm
authors.forename: Sébastien H
authors.initials: SH
authors.lastname: Bauquier
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use; D000769:Anesthesia, Inhalation / Q000662:veterinary; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D002077:Butorphanol / Q000008:administration & dosage / Q000627:therapeutic use*; D002371:Cat Diseases / Q000188:drug therapy*; D002415:Cats; D004334:Drug Administration Schedule; D005260:Female; D007530:Isoflurane / Q000008:administration & dosage / Q000494:pharmacology; D008691:Methadone / Q000008:administration & dosage / Q000627:therapeutic use*; D010146:Pain / Q000188:drug therapy / Q000662:veterinary*; D010149:Postoperative Pain / Q000517:prevention & control / Q000662:veterinary*; D059035:Perioperative Period
chemical_list: D000701:Analgesics, Opioid; D018685:Anesthetics, Inhalation; D007530:Isoflurane; D002077:Butorphanol; D008691:Methadone