Acute damage of gastroduodenal mucosa by acetylsalicylic acid: no prolonged protection by antacids.

Twenty healthy volunteers participated in a double-blind, crossover study to evaluate endoscopically whether low-dose antacids have any prolonged and pH-independent protective capacity against gastroduodenal mucosal damage induced by acetylsalicylic acid. Antacid or placebo one tablet q.d.s. was given for 1.5 days. Acetylsalicylic acid (1.5 g) was administered 3 h after the last dose of antacid/placebo, and gastroscopy was performed 1 h thereafter. Thirteen of 20 subjects showed a decrease in total damage with antacids as compared with placebo, but the difference did not reach statistical significance. Thus, protection by antacids against acetylsalicylic acid-induced gastric mucosal lesions could not be documented at a time when intragastric pH presumably had returned to normal.