Gastric adaptation occurs with aspirin administration in man.

Endoscopy has become a standard method to evaluate drug-induced damage to the gastroduodenal mucosa; however, studies defining the time course, extent, and duration of the injury in man are unavailable. We report a systematic endoscopic evaluation of the effect of aspirin administration on the gastric mucosa in normal volunteers. Aspirin (2.6 g/ day) or placebo was administered for 1 or 7 days. Gastroscopy was performed after 1, 2, 4, and 8 days, and every other day thereafter until the lesions resolved. Submocosal hemorrhages and/or focal erosions were present within 24 hr in all subjects. With continuous aspirin administration, injury was maximal within 3 days and then lessened, ie, damage present after 7 days of aspirin was significantly less than after 1 day of therapy. The time to resolution of the damage was also longer following 1 day than after 7 days of aspirin (median 8 days for 1 day of aspirin vs median 3 days for 7 days of aspirin). Thus, gastric mucosal adaptation occurred and was associated both with less damage and with an accelerated healing process. Acute administration of aspirin produced well-defined areas of submucosal hemorrhages within 2 hr of administration; additional doses increased the area of involvement but not necessarily the severity of involvement.