Gastroscopic evaluation of the effect of aspirin and oxaprozin on the gastric mucosa.

Oxaprozin, a new long-acting, antiinflammatory agent, and aspirin were compared utilizing gastroscopic evaluation and photography of the gastric mucosa in a double-blind, crossover study in normal volunteers. Submucosal hemorrhages or mucosal bleeding was observed in seven of eight subjects on aspirin and in only two of eight on oxaprozin (P = 0.061). Adverse effects were experienced by seven of eight subjects after the aspirin treatment period--tinnitus in five and gastrointestinal symptoms in four. Only one patient had mild diarrhea on oxaprozin. The incidence of adverse effects was found significantly higher with aspirin therapy (P less than 0.001). No laboratory abnormalities of clinical significance were attributed to either drug administration. Results after ten days of treatment show that oxaprozin in therapeutic dose levels (1200 mg once a day) produces significantly fewer changes in the gastric mucosa than aspirin (975 mg administered four times a day, total daily dose 3.9 Gm) in the same subjects, who received both drugs in this double-blind, crossover experiment with a four-week washout period between treatments.