title: Analgesic effects of butorphanol in horses: dose-response studies.
abstract: The analgesic effects of butorphanol (0.05, 0.1, 0.2, and 0.4 mg/kg), pentazocine (2.2 mg/kg), and butorphanol vehicle (0.04 ml/kg) were observed in 6 horses. These horses were instrumented to measure response objectively to painful superficial and visceral stimuli. The tested drugs were given IV according to a Latin square design. After preinjection base-line measurements were made, the analgesic effects were observed at 15 and 30 minutes and then at 30-minute intervals until postinjection minute 240. Analgesic effects of butorphanol were dose-related, with durations between 15 and 90 minutes. Duration of analgesia after pentazocine (2.2 mg/kg) was given was between 15 and 30 minutes. When compared with pentazocine, the 0.4 mg/kg dose of butorphanol provided a more intense and longer period of analgesia. A butorphanol dose of 0.2 mg/kg IV appears optimal. On a dose-body weight basis, the potency of butorphanol was 10 to 17 times that of pentazocine. Behavioral side effects were noted with both agents and were dose-related.
mesh_terms: D000698:Analgesia / Q000662:veterinary*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002077:Butorphanol / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006736:Horses; D008297:Male; D009019:Morphinans / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D010423:Pentazocine / Q000008:administration & dosage / Q000494:pharmacology; D014677:Pharmaceutical Vehicles; D012768:Shivering / Q000187:drug effects
chemical_list: D009019:Morphinans; D014677:Pharmaceutical Vehicles; D002077:Butorphanol; D010423:Pentazocine