Plasma concentrations of flunixin in the horse: its relationship to thromboxane B2 production.

This study investigates the effects of the drug Flunixin on Thromboxane B2 (TxB2) concentrations in horses of different age groups and activity levels. The research found significant variances in TxB2 concentrations between older and younger horses and changes in TxB2 suppression based on different exercise levels after Flunixin administration.

Research Process

The study involved horses falling into two major categories; 2-year-old Thoroughbreds in training and sedentary horses under and over 10 years old. The drug Flunixin meglumine was intravenously administered with a dosage of 1.1 mg/kg.

For the study, the researchers kept track of various parameters including:

• The baseline TxB2 serum concentrations generated during clotting.
• The reduction in TxB2 production at different times after the administration of the drug Flunixin.
• The difference in the effect of Flunixin on the younger, thoroughly trained horses, and the older sedentary horses.

Findings

The researchers observed and reported the following findings:

• A significant difference in baseline TxB2 concentrations between the older and younger horses, indicating a correlation between age and TxB2 serum levels.
• A significant reduction was noted in TxB2 production from the baselines at 1 hour and 4 hours after the administration of Flunixin, but no significant change was reported at 8 hours. This suggests that the effect of the drug on TxB2 concentration wears off over time.
• In the case of younger Thoroughbreds under training, Flunixin caused a higher reduction of TxB2 concentration compared to sedentary horses.

Conclusion

The study indicates that there is a difference in the concentration of TxB2 produced in the blood of older versus younger horses and there is an observed variance between trained and sedentary horses after the administration of Flunixin.

The research also suggests that low concentrations of Flunixin detected in urine 24 hours after administration may not truly represent the pharmacologically effective concentrations of Flunixin in plasma. This information is significant for understanding flunixin’s usage and effectiveness in equine medicine.