OBJECTIVE

To evaluate the musculoskeletal analgesic effect of etodolac administered PO every 12 or 24 hours in chronically lame horses by use of force plate analysis.

METHODS

22 horses with navicular syndrome.

METHODS

Horses received etodolac (23 mg/kg, PO, q 12 h; n = 7), etodolac (23 mg/kg, PO, q 24 h; 8), or corn syrup (20 mL, PO, q 24 h; control treatment; 7) for 3 days. Combined forelimb peak vertical ground reaction force (PVF) was measured via force plate analysis before the first treatment (baseline) and at 6, 12, 24, and 36 hours after the last treatment. Differences in mean PVF (mPVF) between baseline and subsequent measurements were analyzed (repeated-measures ANOVA) and evaluated for treatment and time effects and treatment-time interaction.

RESULTS

Once- or twice-daily administration of etodolac resulted in significant increases in mPVF from baseline at 6, 12, and 24 hours after the last treatment, compared with the control treatment. There were no significant differences in mPVF between the etodolac treatment groups at any time point. In both etodolac treatment groups, there was a significant increase in mPVF from baseline at 6, 12, and 24 hours, compared with that at 36 hours. Etodolac-associated adverse effects were not detected.

CONCLUSIONS

In horses with navicular syndrome, once-daily oral administration of 23 mg of etodolac/kg appears to provide effective analgesia for as long as 24 hours. Twice-daily administration of etodolac at this same dose does not appear to provide any additional analgesic efficacy or duration of effect.