title: Nalbuphine and butorphanol reverse opioid-induced respiratory depression but increase arousal in etorphine-immobilized goats (Capra hircus).
abstract: OBJECTIVE
  To evaluate and compare the efficacy of two opioid agonist-antagonists, nalbuphine and butorphanol, in reversing etorphine-induced respiratory depression in immobilized goats.
  
  
  METHODS
  Prospective, crossover, experimental trial conducted at 1753 m.a.s.l.
  
  
  METHODS
  Eight adult female Boer goats (Capra hircus).
  
  
  METHODS
  Eight minutes following immobilization with an intramuscular injection of 0.1 mg kg(-1) etorphine, goats were given one of nalbuphine (0.8 mg kg(-1) ), butorphanol (0.1 mg kg(-1) ) or sterile water intravenously, in random order in three trials. Respiratory rate (fR ), ventilation, tidal volume, oxygen consumption (V˙O2 ) and carbon dioxide production (V˙CO2 ) were measured continuously. Arterial blood samples to determine PaO2 and PaCO2 were taken 2 minutes before and at 5 minute intervals after etorphine administration for 25 minutes.
  
  
  RESULTS
  Both nalbuphine and butorphanol increased mean PaO2 from 44 mmHg (5.9 kPa) to 63 mmHg (8.4 kPa) after etorphine administration. Butorphanol, but not nalbuphine, also corrected hypopnea and hypoventilation such that fR increased from 13 ± 4 to 21 ± 7 breaths minute(-1) (compared with 16 ± 6 breaths minute(-1) following nalbuphine) and ventilation increased from 4.69 ± 3.04 to 6.91 ± 4.42 L minute(-1) following butorphanol administration. Despite decreases in PaCO2 following nalbuphine and butorphanol, PaCO2 remained elevated compared with pre-immobilization values [nalbuphine: 34 ± 3 mmHg (4.5 ± 0.3 kPa); butorphanol: 34 ± 2 mmHg (4.5 ± 0.3 kPa)] throughout the immobilization. Both agents also decreased the level of immobilization, and increased V˙O2 and V˙CO2 .
  
  
  CONCLUSIONS
  Nalbuphine and butorphanol significantly improved respiratory function in immobilized goats, with butorphanol eliciting a greater positive response than nalbuphine. However, both opioid agonist-antagonists partly reversed etorphine-induced immobilization.
  
  
  CONCLUSIONS
  Butorphanol and nalbuphine can be used to improve respiratory parameters in etorphine-immobilized wildlife, with butorphanol being more effective, but unwanted arousal can occur.
authors.affiliation: Brain Function Research Group, Faculty of Health Sciences, School of Physiology, University of the Witwatersrand, Joahnnesburg, South Africa.
authors.forename: Anna J
authors.initials: AJ
authors.lastname: Haw
authors.affiliation: Brain Function Research Group, Faculty of Health Sciences, School of Physiology, University of the Witwatersrand, Joahnnesburg, South Africa.|Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
authors.forename: Leith Cr
authors.initials: LC
authors.lastname: Meyer
authors.affiliation: Brain Function Research Group, Faculty of Health Sciences, School of Physiology, University of the Witwatersrand, Joahnnesburg, South Africa.|Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
authors.forename: Andrea
authors.initials: A
authors.lastname: Fuller
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D002077:Butorphanol / Q000494:pharmacology*; D018592:Cross-Over Studies; D005048:Etorphine / Q000494:pharmacology*; D005260:Female; D006041:Goats; D007103:Immobilization; D009266:Nalbuphine / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000139:chemically induced / Q000188:drug therapy
chemical_list: D000701:Analgesics, Opioid; D009292:Narcotic Antagonists; D005048:Etorphine; D009266:Nalbuphine; D002077:Butorphanol
keywords: immobilization; mixed opioid agonist-antagonists; opioids; wildlife