Intragastric pH during Treatment with Omeprazole: Role of Helicobacter pylori and H. pylori-Associated Gastritis

Abstract

Background: Omeprazole treatment produces lower intragastric pH values 4 weeks after cure of Helicobacter pylori infection than before. We therefore investigated the effect of healing H. pylori-associated gastritis on intragastric pH in the presence and in the absence of omeprazole therapy. Methods: Before and on day 8 of omeprazole, 20 mg once daily, 24-h intragastric pH-recordings were performed in 14 subjects with H. pylori infection and repeated 4 and 52 weeks after cure of infection. Gastritis severity in corpus and antrum was graded by using a modified Sydney system. Results: In the absence of omeprazole administration, median 24-h pH values before cure did not differ from those 4 and 52 weeks after cure. On day 8 of omeprazole administration, 24-h pH values were much higher before cure (median, 5.15; 95% confidence interval (CI), 4.3–6.0) than 4 weeks (3.6; 2.1–4.4; P < 0.001) and 52 weeks after cure (3.0; 2.1–4.4; P < 0.001). The activity of corpus and antral gastritis was not associated with the magnitude of H⁺ change induced by omeprazole. Conclusion: The increased pH produced by omeprazole during H. pylori infection is likely to be due to neutralizing substances produced by H. pylori and not to H. pylori-induced gastritis.

Key Words:

• Antisecretory drugs
• gastric acidity
• gastric pH-metry
• gastritis
• Helicobacter pylori
• omeprazole