Effect of nizatidine and cimetidine on betazole-stimulated gastric secretion of normal subjects: comparison of effects on acid, water, and pepsin.

The effect of nizatidine, a new histamine H2 receptor antagonist, on gastric secretory function of eight normal subjects stimulated with betazole, was compared with that of cimetidine. Single oral doses of 75 mg, 150 mg, and 300 mg nizatidine, 300 mg cimetidine, and a placebo were administered on separate occasions 1 h before betazole stimulation. Gastric secretions were recovered in 15-min fractions for the ensuing 2 h, and the pH, H+ concentration and output, volume, and pepsin concentration and output were determined. Doses of 150 mg and 300 mg nizatidine depressed the secretory response significantly more than did cimetidine. The antisecretory effects of 75 mg nizatidine was no different than that of 300 mg cimetidine. Nizatidine 300 mg inhibited pepsin output significantly more than volume. Although pepsin concentration was reduced more than volume, the difference was not significant. These observations, in contrast to results of previous studies, suggest a direct inhibition of pepsin secretion, although to a lesser extent than that of acid.