Effectiveness of administration of phenylbutazone alone or concurrent administration of phenylbutazone and flunixin meglumine to alleviate lameness in horses.

The study looks into the efficiency of two treatment approaches – the use of phenylbutazone alone and its combination with flunixin meglumine – in reducing lameness in horses. The combination of the two drugs was found to be more effective, though certain potential adverse effects were noted.

Methodology

• The study involved 29 adult horses that naturally exhibited symptoms of forelimb and hind limb lameness.
• Kinematic evaluations were used to assess lameness, with the evaluations being performed as the horses trotted on a treadmill both before and after two different treatment regimens involving non steroidal anti-inflammatory drugs (NSAIDs).
• The first regimen involved the administration of phenylbutazone paste at an approximate dose of 2.2 mg/kg, orally, every 12 hours for 5 days. The second regimen integrated the same dosage and administration rate of phenylbutazone paste with the addition of flunixin meglumine administered at 1.1 mg/kg, intravenously, every 12 hours for 5 days.

Results

• The combined administration of NSAIDs resulted in a more significant decrease in lameness compared to the administration of phenylbutazone alone.
• There was an improvement in the horses after the combined use of NSAIDs, but it did not utterly suppress lameness.
• Five of the horses did not show any improvement after either of the NSAID treatment regimens.
• All plasma concentrations of NSAIDs after treatments were lower than the current limit set by the United States Equestrian Federation Inc for a single NSAID.
• However, one of the horses treated with the combined NSAID regimen died of acute necrotizing colitis during the study. This hints at potential toxic side effects.

Conclusions

• Overall, the study found that the combined administration of NSAIDs, specifically phenylbutazone and flunixin meglumine, was more effective in alleviating lameness in horses than the administration of phenylbutazone alone.
• Despite this, the potential toxic side effects, as evidenced by the death of one horse during the study, suggest that caution should be exercised when considering the use of combined NSAIDs.