Effect of etodolac on articular and bone pathology associated with adjuvant arthritis in rats: a comparison with aspirin and naproxen.

The effect of treatment with the new anti-inflammatory drug etodolac on the articular and bone pathology associated with adjuvant arthritis in rats has been compared to the effects produced by aspirin and naproxen. Five measures of drug effect were made (changes in hind paw edema, body weight, normal hind leg function and articular damage as assessed by radiologic and histopathologic techniques). Drug treatment was initiated 16 days after adjuvant injection when arthritis was already established and continued for either 14 or 28 days. Etodolac produced a dose-related inhibition of all arthritic changes. Results from the radiologic study indicated that etodolac not only prevented the further development of articular damage by arthritis but actually caused a regression of these lesions established before drug treatment began. Similar results were obtained from the histopathologic study. Naproxen prevented the further development of arthritic damage but aspirin, although it decreased hind paw edema and increased body weight gains, had no significant effect on the articular damage produced by arthritis.