Antacids and gastric mucosal protection.

Aluminum hydroxide-containing antacids have a protective effect on the stomach in that they prevent grossly visible mucosal necrosis and hemorrhages produced by noxious agents, such as aspirin or absolute ethanol. Histologically, this protective effect is mainly confined to the tissue located deep in the gastric mucosa, essentially comprising gastric glands, while the damage to the surface epithelium is not significantly lessened. Accordingly, integrity parameters of the superficial epithelial layer (potential difference, mucous secretion, cell desquamation) do not indicate a protective action of antacids against damage by necrotizing agents. By contrast, significantly diminished microbleeding rates do suggest that protection by antacids works at a deeper level within the mucosa. The protective action of antacids may be mediated, at least partly, by endogenous prostaglandins, which were found to be elevated in this context.