The use of force plate measurements to titrate the dosage of a new COX-2 inhibitor in lame horses.
Authors: Back W, MacAllister C G, van Heel M C V, Pollmeier M, Hanson P D
Journal: Equine veterinary journal
Summary
# Editorial Summary: Firocoxib Dosing in Osteoarthritic Lameness Force plate analysis has become the gold standard for objectively quantifying lameness improvement in clinical trials, yet optimal dosing strategies for newer anti-inflammatory agents remain poorly defined. Back and colleagues evaluated firocoxib, a selective COX-2 inhibitor, across four dosage regimens in 64 chronically lame horses with presumed osteoarthritis (including navicular disease) using peak vertical force (PVF) measurements and clinical grading over a seven-day treatment period. Horses receiving 0.1 and 0.25 mg/kg bodyweight daily showed significant improvements in PVF by days 2 and 6 compared to vehicle control, with both groups achieving greater than one-grade reduction in clinical lameness by day 6; critically, the higher dose of 0.25 mg/kg did not produce superior outcomes to 0.1 mg/kg, establishing 0.1 mg/kg once daily as the minimally effective therapeutic dose. For practitioners managing chronic joint disease, these findings provide evidence-based dosing guidance that optimises anti-inflammatory efficacy whilst potentially reducing unnecessary drug exposure, though individual response variation and concurrent management strategies should continue to inform clinical decision-making on a case-by-case basis.
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Practical Takeaways
- •Firocoxib at 0.1 mg/kg once daily is the effective dose for treating chronic osteoarthritis-related lameness in horses, with measurable improvements within 2-6 days of treatment
- •Force plate measurements provide objective evidence of lameness improvement that may not be apparent on clinical grading alone, useful for evaluating treatment response
- •Higher doses (0.25 mg/kg) offer no additional benefit over the 0.1 mg/kg dose, suggesting dose optimization can reduce costs without sacrificing efficacy
Key Findings
- •Firocoxib at 0.1 mg/kg bwt once daily significantly improved peak vertical force (PVF) measurements at Days 2 and 6 compared to vehicle control (P < 0.05)
- •Mean clinical lameness grades decreased by >1 grade at Day 6 with both 0.1 and 0.25 mg/kg bwt doses
- •The 0.1 mg/kg bwt dose was as effective as the 0.25 mg/kg bwt dose, making it the optimal therapeutic dosage
- •Force plate analysis of peak vertical force proved superior to lameness grading alone for detecting drug efficacy