Effect of curing Helicobacter pylori infection on intragastric acidity during treatment with ranitidine in patients with duodenal ulcer.

BACKGROUND In patients with duodenal ulcer cure of Helicobacter pylori infection resulted in a pronounced decrease in intragastric pH during treatment with omeprazole. AIM To test the hypothesis that treatment of H pylori adversely affects the pH response to ranitidine. PATIENTS Eighteen patients with duodenal ulcer who were infected with H pylori were studied. METHODS Twenty four hour pH recordings were performed during treatment with ranitidine (300 mg) at night before and four to six weeks after cure of H pylori infection. Presence of H pylori was assessed by a rapid urease test, culture, histology, and a 13C urea breath test. Also, the fasting gastrin concentrations were measured before and after treatment for H pylori infection. RESULTS Cure of H pylori infection resulted in a considerable improvement in both antral and corpus gastritis and a decrease in fasting gastrin concentrations. As a result of the cure the night time intragastric pH during treatment with ranitidine decreased (median pH 6.8 v 5.4; p = 0.007), whereas the acidity during the daytime was not affected. CONCLUSIONS In patients with duodenal ulcer the intragastric pH during treatment with ranitidine depends on H pylori. However, the loss of effectiveness in altering pH seems to be less pronounced than previously found with omeprazole.