Efficacy of cyclo-oxygenase inhibition by two commercially available firocoxib products in horses

In this model, the canine chewable preparation of firocoxib was as effective as the equine paste formulation at reducing LPS-induced PGE&sub2; synthesis. Potential relevance: The canine chewable preparation of firocoxib may be a suitable alternative to the paste formulation in horses for situations where extra-label drug use can be legally justified. The Summary is available in Chinese - see Supporting information.

Horses received 57 mg of the assigned firocoxib preparation orally once daily for 7 days, with a 14 day washout period between drug crossover. Ten healthy adult light breed horses were used as no-treatment controls. During each treatment period, blood was taken before dosing on Days 0 and 7 and on Day 7 1 h after dosing for ex vivo lipopolysaccharide (LPS) stimulation to induce (PGE&sub2; ) synthesis. Heparinised plasma was also collected on Day 7 immediately prior to and 1 h after dosing to determine plasma firocoxib concentrations.

To determine the relative efficacy of 2 commercially available firocoxib products to inhibit prostaglandin E&sub2; (PGE2) synthesis after oral dosing in horses. Study design: A crossover design using 8 adult horses (n = 4 for each preparation during each treatment period). Body weight range 532-614 kg.

In the control group, there was no significant change in LPS-induced PGE2 over time. In contrast, immediately prior to and 1 h after treatment on Day 7, the mean LPS-induced PGE&sub2; concentration decreased significantly compared to Day 0 values in all treated horses. There was no difference in PGE&sub2; or plasma firocoxib concentrations between firocoxib treatment groups.