COMPARATIVE EFFECTS OF NABUMETONE, NAPROXEN, PIROXICAM, AND DICLOFENAC ON RAT GASTRIC IRRITANCY FOLLOWING ACUTE EXPOSURE TO OTC NONSTEROIDAL ANTIINFLAMMATORY AGENTS AND OTHER GASTRIC IRRITANTS

This study examined the relative effects of equally-effective anti-inf lammatory doses of nabumetone, naproxen, piroxicam and diclofenac on g astric irritancy induced by over-the-counter (OTC) non-steroidal anti- inflammatory drugs (NSAIDs) aspirin and ibuprofen and a variety of nec rotizing agents (0.6 N HCl, 0.2 N NaOH and 25% NaCl). Within one hour, aspirin 100 and 200 mg/kg and ibuprofen up to 15 mg/kg produced signi ficant gastric mucosal injury. Aspirin 50 mg/kg produced only minimal damage that was enhanced by 5 x ID25 piroxicam and naproxen, but not b y nabumetone or diclofenac. 5 xID(25) naproxen, piroxicam, and diclofe nac significantly enhanced mucosal damage produced by ibuprofen 2.5 mg /kg. An equivalent anti-inflammatory dose of nabumetone failed to enha nce the gastric irritancy produced by ibuprofen 2.5 mg/kg. Similarly, naproxen, piroxicam, and diclofenac enhanced the susceptibility of the gastric mucosa to the necrotizing actions of 0.6 N HCl, 0.2 N NaOH or 25% NaCl. Naproxen, piroxicam, or diclofenac are more likely than nab umetone to enhance gastric mucosal injury produced by OTC NSAIDs (aspi rin and ibuprofen) or other gastric irritants.