Endoscopic findings in the stomach and duodenum after treatment with enteric-coated and plain naproxen tablets in healthy subjects.

To compare the damaging effect of enteric-coated and plain naproxen tablets on the gastric and duodenal mucosa, 12 healthy subjects were studied before and after 2 7-day treatment periods in a randomized, double-blind, double-dummy, crossover trial. Both preparations of the drug caused mucosal lesions, but the extent of the damage was significantly less in the stomach and duodenum after enteric-coated than after plain naproxen tablets. The subjects, however, did not have a preference for either preparation. The morning plasma naproxen concentration was significantly higher after treatment with enteric-coated naproxen than after treatment with plain tablets. The results of the study indicate that naproxen damages the mucosa of the stomach and duodenum through local and systemic effects. The local effect seems to be the more important and can at least be partially prevented by enteric-coating of the tablets.