title: Comparative study on the sedative effects of morphine, methadone, butorphanol or tramadol, in combination with acepromazine, in dogs.
abstract: OBJECTIVE
  To compare the effects of morphine (MOR), methadone (MET), butorphanol (BUT) and tramadol (TRA), in combination with acepromazine, on sedation, cardiorespiratory variables, body temperature and incidence of emesis in dogs.
  
  
  METHODS
  Prospective randomized, blinded, experimental trial.
  
  
  METHODS
  Six adult mixed-breed male dogs weighing 12.0 +/- 4.3 kg.
  
  
  METHODS
  Dogs received intravenous administration (IV) of acepromazine (0.05 mg kg(-1)) and 15 minutes later, one of four opioids was randomly administered IV in a cross-over design, with at least 1-week intervals. Dogs then received MOR 0.5 mg kg(-1); MET 0.5 mg kg(-1); BUT 0.15 mg kg(-1); or TRA 2.0 mg kg(-1). Indirect systolic arterial pressure (SAP), heart rate (HR), respiratory rate (f(R)), rectal temperature, pedal withdrawal reflex and sedation were evaluated at regular intervals for 90 minutes.
  
  
  RESULTS
  Acepromazine administration decreased SAP, HR and temperature and produced mild sedation. All opioids further decreased temperature and MOR, BUT and TRA were associated with further decreases in HR. Tramadol decreased SAP whereas BUT decreased f(R) compared with values before opioid administration. Retching was observed in five of six dogs and vomiting occurred in one dog in MOR, but not in any dog in the remaining treatments. Sedation scores were greater in MET followed by MOR and BUT. Tramadol was associated with minor changes in sedation produced by acepromazine alone.
  
  
  CONCLUSIONS
  When used with acepromazine, MET appears to provide better sedation than MOR, BUT and TRA. If vomiting is to be avoided, MET, BUT and TRA may be better options than MOR.
authors.affiliation: Faculty of Veterinary Medicine, Centro Universitário de Maringá (CESUMAR), Paraná, Brazil. btraposo@hotmail.com
authors.forename: Eduardo Raposo
authors.initials: ER
authors.lastname: Monteiro
authors.forename: Adolfo Rodrigues
authors.initials: AR
authors.lastname: Junior
authors.forename: Hemir Martins Quirilos
authors.initials: HM
authors.lastname: Assis
authors.forename: Daniela
authors.initials: D
authors.lastname: Campagnol
authors.forename: Juliany Gomes
authors.initials: JG
authors.lastname: Quitzan
mesh_terms: D000075:Acepromazine / Q000008:administration & dosage / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000494:pharmacology*; D000771:Anesthesia, Intravenous / Q000662:veterinary; D018686:Anesthetics, Intravenous / Q000008:administration & dosage* / Q000494:pharmacology; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D002077:Butorphanol / Q000008:administration & dosage / Q000494:pharmacology; D018592:Cross-Over Studies; D004283:Dog Diseases / Q000139:chemically induced; D004285:Dogs; D018492:Dopamine Antagonists / Q000008:administration & dosage* / Q000494:pharmacology*; D004359:Drug Therapy, Combination; D006993:Hypnotics and Sedatives; D008297:Male; D008691:Methadone / Q000008:administration & dosage / Q000494:pharmacology; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology; D014147:Tramadol / Q000008:administration & dosage / Q000494:pharmacology; D014839:Vomiting / Q000139:chemically induced
chemical_list: D000701:Analgesics, Opioid; D018686:Anesthetics, Intravenous; D018492:Dopamine Antagonists; D006993:Hypnotics and Sedatives; D014147:Tramadol; D000075:Acepromazine; D009020:Morphine; D002077:Butorphanol; D008691:Methadone