Helicobacter pylori augments the pH-increasing effect of omeprazole in patients with duodenal ulcer

Background & Aims: Omeprazole is less effective in healthy subjects than in patients with duodenal ulcers, The aim of this study was to determine whether Helicobacter pylori augments the pH-increasing effect of omeprazole in patients with duodenal ulcers, Methods: In 16 patients with duodenal ulcers, baseline intragastric acidity was measured before and 4-6 weeks after the cure of H. pylori infection, In 17 patients with duodenal ulcers, 24-hour pH metry was performed during treatment with 20 mg omeprazole once daily before as well as after eradication of H. pylori. Intragastric acidity was measured using a glass electrode placed 5 cm below the cardia, H. pylori infection was assessed by [C-13] urea breath test, culture, histology, and rapid urease test, Results: H. pylori eradication resulted in a marked decrease of the pH-increasing effect of omeprazole (24-hour median gastric pH, 5.5 vs, 3.0; P < 0.002) that was most pronounced during nighttime (median gastric pH, 6.4 vs, 2.1; P = 0.001), On the other hand, baseline intragastric pH remained unchanged after eradication (median gastric pH, 1.0 vs, 1.1; P = 0.5), Conclusions: In patients with duodenal ulcers treated with omeprazole, intragastric pH depends significantly on the presence or absence of H. pylori, whereas baseline pH remained unchanged after H. pylori eradication.