The effect of Helicobacter pylori eradication on intragastric pH during dosing with lansoprazole or ranitidine

Background: The antisecretory effect of omeprazole on intragastric pH is de creased in the absence of Helicobacter pylori. Aim: To investigate the effect of H. pylori eradication on intragastric pH during lansoprazole or ranitidine dosing in 41 asymptomatic H. pylori-posit ive subjects. Method: Two groups of healthy H. pylori-positive volunteers were investigat ed. One group was dosed with lansoprazole 30 mg at 08.00 hours for at least 8 days, before and after 2 weeks of placebo-controlled double-blind eradic ation therapy using ranitidine bismuth citrate 400 mg b.d. and clarithromyc in 500 mg b.d. The other group was dosed with ranitidine 300 mg at 23.00 ho urs for at least 8 days using the same trial design. An upper endoscopy was performed to establish H. pylori status by rapid urease test, culture and histology before both periods of dosing. Twenty-four hour intragastric pH r ecording was performed on the final day of all periods of dosing. Results: H. pylori eradication significantly decreased the intragastric pH reached during lansoprazole treatment throughout all periods of the day. In tragastric pH during ranitidine treatment was not affected by H. pylori era dication, except for the late-night period. Conclusion: H. pylori eradication has a more pronounced effect on the acid- inhibiting properties of lansoprazole than on those of ranitidine.