Effect of cimetidine on intrinsic factor and pepsin secretion in man.

The effect of cimetidine on gastric acid, pepsin, and intrinsic factor secretion was assessed in normal male subjects. Cimetidine (300 mg) completely inhibited acid, pepsin, and intrinsic factor concentration and output stimulated by betazole. In contrast, basal output of pepsin and intrinsic factor was not inhibited. We conclude that H2-receptor antagonists inhibit betazole stimulation of intrinsic factor output in addition to their well-known inhibition of acid secretion.