Dr Ruemmler's current address is Boston Equine Associates, 28 Tremont Street, Rehoboth, Massachusetts 02769, USA.
Phenylbutazone and flunixin meglumine used singly or in combination in experimental lameness in horses
Article first published online: 15 NOV 2011
© 2011 EVJ Ltd
Equine Veterinary Journal
Special Issue: 57th Annual Convention of the American Association of Equine Practitioners
Volume 43, Issue Supplement s40, pages 12–17, November 2011
How to Cite
FOREMAN, J. H. and RUEMMLER, R. (2011), Phenylbutazone and flunixin meglumine used singly or in combination in experimental lameness in horses. Equine Veterinary Journal, 43: 12–17. doi: 10.1111/j.2042-3306.2011.00485.x
- Issue published online: 15 NOV 2011
- Article first published online: 15 NOV 2011
- [Paper received for publication 18.03.11; Accepted 20.06.11]
- nonsteroidal anti-inflammatory drug;
- plasma concentration;
Reason for performing study: Using an adjustable heart bar shoe model of foot pain, the objective of this study was to test the hypothesis that the combined use of phenylbutazone (PBZ) and flunixin meglumine (FM) would prove more efficacious in alleviating lameness than either drug alone.
Materials and methods: One hour after induction of lameness at weekly intervals, 8 healthy adult Thoroughbred horses randomly underwent one of 4 i.v. treatments: saline (SAL) placebo (1 ml/45 kg bwt), PBZ (4.4 mg/kg bwt), FM (1.1 mg/kg bwt) or PBZ+FM (at the same dosages as given individually). Heart rate (HR) and lameness score (LS) responses were assessed in a blinded manner every 20 min for 5 h after lameness induction and then hourly for 12 h after treatment. Jugular venous blood samples were obtained at -1, 0, 0.05, 1, 2, 4, 6, 8, 10 and 12 h and subsequently analysed for drug concentrations. Repeated measures ANOVA and post hoc Tukey's test were used to identify analgesic effects at a significance level of P<0.05.
Results: Heart rate was lower in all nonsteroidal anti-inflammatory drug (NSAID)-treated trials from 2 h to 10 h post treatment (P<0.05). Analgesic effects of FM and PBZ+FM, as evidenced by decreases in HR, lasted for 12 h post treatment (P<0.05). Lameness score decreased earlier in PBZ and PBZ+FM trials than in FM trials (P<0.05) and the analgesic effect on LS lasted for 12 h post treatment for all NSAID trials (P<0.05). Peak PBZ plasma concentration was 73.7 ± 6.0 and 77.9 ± 5.5 µg/ml. Peak FM concentration was 12.0 ± 0.8 and 13.7 ± 1.0 µg/ml
Conclusions: It was concluded that the combination of PBZ+FM was not more effective than either PBZ or FM alone. These data do not support the hypothesis that the combination is more efficacious at these dosages than either drug alone in this model of acute foot pain.