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Dose titration of the clinical efficacy of intravenously administered flunixin meglumine in a reversible model of equine foot lameness
Author(s) -
Foreman J. H.,
Bergstrom B. E.,
Golden K. S.,
Roark J. J.,
Coren D. S.,
Foreman C. R.,
Schumacher S. A.
Publication year - 2012
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.2012.00655.x
Subject(s) - lameness , dose , medicine , horse , heart rate , saline , anesthesia , pharmacodynamics , pharmacokinetics , surgery , blood pressure , paleontology , biology
Summary Reasons for performing study There are no refereed controlled documentations of the skeletal analgesic efficacy of different dosages of flunixin meglumine ( FM ). Objectives The objective of this experiment was to compare the efficacy of various dosages of FM with a negative control. The hypothesis was that higher doses would result in improved efficacy in a dose‐dependent manner when tested in a reversible model of foot lameness. Methods Ten horses shod with adjustable heart bar shoes had weekly modified AAEP g rade 4.0/5.0 lameness induced by tightening a set screw against the heart bar. Heart rate ( HR) and lameness score ( LS ) were monitored by one double‐blinded investigator at rest; every 20 min after lameness induction for 5 h and hourly for another 8 h. One hour after lameness induction, treatments were administered i.v. in a randomised order: negative control (isotonic saline: SAL ) or FM at 0.55 (half‐dose), 1.1 (single‐dose) or 2.2 (double‐dose) mg/kg bwt. Results were compared using RM ANOVA and Student–Newman–Keul's test with the level of significance set at P <0.05. Results Compared to SAL , half‐dose FM reduced HR at 2.33, 2.67, 4.0–8.0, and 10.0 h and LS at 1.33–12.0 h ( P <0.05). Single‐ and double‐dose FM reduced HR from 0.67 to 12.0 h and LS from 1.0 to 12.0 h post administration ( P <0.05). Compared with half‐dose FM , single‐ and double‐dose LS were further decreased from 1.67 to 12.0 h post administration ( P <0.05). Mean peak and decaying plasma FM concentrations were different between dosages in a dose‐dependent manner through 6 h post administration ( P <0.05). Conclusions Flunixin meglumine administration affected dependent variables in a dose‐dependent manner with half‐dose FM clinically effective for a shorter period. Higher dosages did not perform differently from one another. Potential relevance Practitioners must be aware that half‐doses of FM are less efficacious than single doses but double doses are not more efficacious and yet are potentially more toxic.