Effect of selective versus nonselective cyclooxygenase inhibitors on gastric ulceration scores and intestinal inflammation in horses.

This research investigates whether a selective cyclooxygenase (COX)-2 inhibitor reduces gastric ulceration and intestinal inflammation in horses compared to a nonselective COX inhibitor. The study found that though both types of nonsteroidal anti-inflammatory drugs (NSAIDs) induce gastric injury in horses, the COX-2 selective inhibitor resulted in less severe injury.

Study Design

• The researchers implemented a randomized block design and used 25 healthy adult horses in their study.
• The horses were randomly given either a placebo, phenylbutazone (a nonselective COX inhibitor), or firocoxib (a COX-2 selective NSAID). These were all administered daily for 10 days.
• Gastroscopies were carried out on the horses on days 0 and 10, and the researchers scored the squamous and glandular ulcers according to predetermined scoring criteria.
• Fecal samples were taken from the horses on days 0, 10, and 20 to test for fecal myeloperoxidase (MPO) concentration.

Results

• Both the phenylbutazone and firocoxib induced gastrointestinal (GI) injury in the horses.
• The damage was determined by gastric ulceration scores and fecal MPO levels.
• Glandular gastric ulceration scores and fecal MPO concentrations were higher in horses treated with phenylbutazone at day 10.
• Increases in fecal MPO decreased significantly 10 days after stopping the firocoxib treatment — however, they remained greater than the baseline for the group that had been given phenylbutazone.

Conclusions

• Both classes of NSAID induced gastric ulceration, but the damage was less severe with the COX-2 selective NSAID firocoxib.
• Fecal MPO levels increased in both groups after 10 days of treatment, but this increase was significant only in the horses receiving the nonselective COX inhibitor phenylbutazone.
• These results suggest that while both types of NSAID induce GI injury in horses, the COX-2 selective NSAID firocoxib resulted in less severe injury at the doses given in this study.