Short-term administration of flunixin meglumine or firocoxib does not alter viscoelastic coagulation profiles in healthy horses.

This study tested whether administering two common painkillers — firocoxib and flunixin meglumine — affected blood clotting in healthy horses. It found that, although some changes were detectable, they were not big enough to be clinically significant.

Study Design

• The research team evaluated the effects of two non-steroidal anti-inflammatory drugs (NSAIDs): firocoxib, which selectively inhibits cyclooxygenase-2 (COX-2), and flunixin meglumine, which is non-selective. The study aimed to see whether these drugs influence coagulation parameters in healthy horses.
• The experiment involved 12 adult mixed-breed horses in a crossover design. Initially, the horses were given flunixin meglumine, a period of 6 months of ‘rest’ was provided to remove any residual drug effects (referred to as the washout period), and later, firocoxib was administered.

Methodology

• The exact dosage of each drug given was as follows: flunixin meglumine at 1.1mg/kg intravenously every 12 hours for 5 days; then, after the 6 month washout period, firocoxib — first at 0.3 mg/kg orally once, and then 0.1 mg/kg orally every 24 hours for the next 4 days.
• The researchers also gave each horse omeprazole (1 mg/kg, orally, once every 24 hours) concurrently with each NSAID. Omeprazole is used here as a safeguard to prevent potential gastric ulcers that may result from NSAID-induced stomach lining erosion.

Measurements

• Before and after administering each NSAID, the researchers took measures of viscoelastic coagulation profiles and traditional coagulation parameters which include prothrombin time, partial thromboplastin time, and fibrinogen. This was done to discern any alterations in the blood clotting ability of the horses.

Results

• The results showed that viscoelastic coagulation parameters were within normal ranges before and after both treatments. However, there was a statistically significant difference between the two treatments in terms of amplitude (clot strength) at a point 10 minutes after clot time and at maximum clot formation. These differences, however, were small and did not have clinical implications.
• Overall, short-term use of both flunixin meglumine and firocoxib did not significantly affect blood clotting profiles in healthy horses.

Conclusion

• The authors concluded that while short-term administration of the NSAIDs tested did not significantly alter blood clotting in healthy horses, clinicians need to be aware of potential issues if these drugs are used for a long duration or used in severely ill horses.
• They suggest more research is necessary to explore possible effects in these scenarios.