title: Effects of single-dose intravenous phenylbutazone on experimentally induced, reversible lameness in the horse.
abstract: The objective was to test the hypothesis that phenylbutazone (PBZ) alleviates lameness in an adjustable heart bar shoe model of equine foot pain. Eight Quarter Horse mares underwent 4-weekly treatments randomly: 0.9% saline placebo (SAL: 1 mL/45 kg body weight i.v.) with no lameness; SAL with lameness; PBZ (4.4 mg/kg body weight i.v.) with no lameness; and PBZ with lameness. Blinded heart rate (HR) and lameness score (LS) were assessed every 20 min for 2 h and then hourly through 9 h. At 1 h SAL or PBZ was administered. Jugular venous samples were obtained at hours 0, 1, 2, 4, 6, and 8 and were evaluated for packed cell volume (PCV), cortisol, and drug concentrations. Repeated measures anova and t-tests were used to identify PBZ effects at a significance level of P<0.05. PBZ-treated LS was lower 2-8 h post-treatment, and HR was lower from 2 through 6 h post-treatment (P<0.05). Phenylbutazone did not change PCV and had minimal effect on cortisol. Mean plasma PBZ and oxyphenbutazone concentrations 7 h after treatment were 7.2-7.5 and 1.6-1.9 microg/mL, respectively. It was concluded that PBZ was efficacious in alleviating lameness in this model. Cortisol and PCV were not discriminating enough to distinguish between PBZ-treated and SAL-treated trials.
authors.affiliation: Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA. jhf@uiuc.edu
authors.forename: J H
authors.initials: JH
authors.lastname: Foreman
authors.forename: A
authors.initials: A
authors.lastname: Barange
authors.forename: L M
authors.initials: LM
authors.lastname: Lawrence
authors.forename: L L
authors.initials: LL
authors.lastname: Hungerford
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D005552:Forelimb / Q000293:injuries; D006339:Heart Rate; D006736:Horses / Q000293:injuries*; D006854:Hydrocortisone / Q000097:blood; D007275:Injections, Intravenous / Q000662:veterinary; D015601:Injury Severity Score; D007794:Lameness, Animal; D010146:Pain / Q000517:prevention & control / Q000662:veterinary*; D010147:Pain Measurement / Q000662:veterinary; D010653:Phenylbutazone / Q000008:administration & dosage / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D010653:Phenylbutazone; D006854:Hydrocortisone