title: Evaluation of dexmedetomidine and ketamine in combination with opioids as injectable anesthesia for castration in dogs.
abstract: OBJECTIVE
  To compare efficacy and cardiorespiratory effects of dexmedetomidine and ketamine in combination with butorphanol, hydromorphone, or buprenorphine (with or without reversal by atipamezole) in dogs undergoing castration.
  
  
  METHODS
  Prospective, randomized, split-plot, blinded study.
  
  
  METHODS
  30 healthy client-owned sexually intact male dogs.
  
  
  METHODS
  Dogs (n = 10 dogs/group) were assigned to receive dexmedetomidine (15 μg/kg [6.82 μg/lb]) and ketamine (3 mg/kg [1.36 mg/lb]) with butorphanol (0.2 mg/kg [0.09 mg/lb]; DKBut), the same dosages of dexmedetomidine and ketamine with hydromorphone (0.05 mg/kg [0.023 mg/lb]; DKH), or the same dosages of dexmedetomidine and ketamine with buprenorphine (40 μg/kg [18.18 μg/lb]; DKBup). All drugs were administered as a single IM injection for induction and maintenance of anesthesia for castration. At conclusion of the surgery, 5 dogs in each treatment group received atipamezole (150 μg/kg [68.18 μg/lb], IM), and the remainder received saline (0.9% NaCl) solution IM. Cardiorespiratory variables and quality of anesthesia were assessed. Supplemental isoflurane was administered to the dogs when anesthesia was considered inadequate during surgery.
  
  
  RESULTS
  All drug combinations rapidly induced anesthesia. Dogs were intubated within 10 minutes after injection. Supplemental isoflurane was needed during surgery in 1, 3, and 4 dogs in the DKBup, DKBut, and DKH groups, respectively. Dogs that received atipamezole had a significantly shorter recovery time. Some dogs in each group had bradycardia and hypoxemia with hypertension.
  
  
  CONCLUSIONS
  DKBup was the most suitable injectable anesthetic combination used. Recovery was shortened by IM administration of atipamezole. There were minimal adverse effects in all groups.
authors.affiliation: Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Michele
authors.initials: M
authors.lastname: Barletta
authors.forename: Brenda R
authors.initials: BR
authors.lastname: Austin
authors.forename: Jeff C
authors.initials: JC
authors.lastname: Ko
authors.forename: Mark E
authors.initials: ME
authors.lastname: Payton
authors.forename: Ann B
authors.initials: AB
authors.lastname: Weil
authors.forename: Tomohito
authors.initials: T
authors.lastname: Inoue
mesh_terms: D058669:Adrenergic alpha-2 Receptor Antagonists / Q000627:therapeutic use; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000768:Anesthesia, General / Q000662:veterinary; D000778:Anesthetics, Dissociative / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000494:pharmacology*; D004285:Dogs; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology; D007093:Imidazoles / Q000627:therapeutic use; D007649:Ketamine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009919:Orchiectomy / Q000662:veterinary*
chemical_list: D058669:Adrenergic alpha-2 Receptor Antagonists; D000701:Analgesics, Opioid; D000778:Anesthetics, Dissociative; D006993:Hypnotics and Sedatives; D007093:Imidazoles; C050701:atipamezole; D020927:Dexmedetomidine; D007649:Ketamine