Effect of Cimetidine and Oxmetidine on 24-h Gastric Acid and Pepsin in Patients

Abstract

The 24-h intragastric pH, titrated hydrogen ion concentration, and pepsin concentration were studied in nine peptic ulcer patients during administration of placebo and of 800 mg cimetidine given as two or four equal doses. Cimetidine, 400 mg twice daily, was more effective in reducing acidity during morning (p < 0.05) and overnight (p < 0.01) than cimetidine, 200 mg four times daily, which, however, was the most effective regimen during the afternoon (p < 0.05–0.01). During the 24-h period pH values equal to or above 5 were observed for less than 1 h with placebo treatment, for 1.8 h with cimetidine, 200 mg four times daily, and for 4.7 h with cimetidine, 400 mg twice daily. A new histamine H₂-receptor antagonist, oxmetidine, was studied in six other patients, also during a 24-h period. Both 400 mg twice daily and 200 mg four times daily of oxmetidine were superior to placebo (p < 0.05) in reducing intragastric acidity during the entire 24-h period.