Effects of Firocoxib, Flunixin Meglumine, and Phenylbutazone on Platelet Function and Thromboxane Synthesis in Healthy Horses.

This research investigates how the administration of certain nonsteroidal anti-inflammatory drugs (NSAIDs) affects the function of platelets and the synthesis of thromboxane in healthy horses. The study found that three specific NSAIDs did not significantly impact platelet function, but two of them did considerably reduce thromboxane synthesis.

Experiment Configuration

• We observe nine healthy adult horses, consisting of six geldings (neutered males) and three mares (females), in a randomized cross-over study.
• These horses receive either flunixin meglumine, phenylbutazone, or firocoxib over five days. The dosages and frequencies are specific to each drug and are administered intravenously (IV).
• The researchers took blood samples from the horses before drug administration (day 0), one hour afterward (day 1), and then one hour post-administration on day 5.
• By employing turbidimetric aggregometry and a platelet function analyzer, the functionality of the platelets is evaluated. Simultaneously, the concentration of thromboxane B in the serum is identified by a commercial ELISA kit.
• Written into the experimentation protocol is a washout period, a minimum of 14 days between each trial to ensure no residual effects of the NSAID remain.

Key Findings

• The results uncover no significant impact on platelet function or aggregation one hour and five days post-administration of any of the three NSAIDs (firocoxib, flunixin meglumine, or phenylbutazone), when assessed using turbidimetric aggregometry or a platelet function analyzer.
• However, a significant decrease in the synthesis of thromboxane is observed at the one hour and five days post-administration points with both flunixin meglumine and phenylbutazone, but not with firocoxib.

Implications and Conclusion

• Based on this model, the researchers conclude that preoperative administration of any of these three NSAIDs – flunixin meglumine, phenylbutazone, or firocoxib – should not inhibit platelet function in horses.
• Still, the study identifies significant reductions in thromboxane B synthesis following the administration of flunixin meglumine and phenylbutazone. The clinical implications of this finding are yet to be determined and could warrant further research.