The effect of intragastric acidity on Helicobacter pylori eradication with bismuth-metronidazole-amoxicillin.

BACKGROUND/AIMS: Adding an acid secretion inhibitor to anti-H. pylori regimens may be potentially valuable for enhancing the effectiveness of antimicrobials that exhibit markedly reduced activity at low pH. This study was conducted to evaluate intragastric acidity as a factor in H. pylori eradication with bismuth-based triple therapy. METHODOLOGY: Forty patients with duodenal ulcer and H. pylori infection were included. The patients were divided into 2 groups--normacid (n = 20) and hyperacid (n = 20)--based on the amount of time that 24-hour intragastric pH took to reach the level pH > or = 3. All patients received bismuth subsalicylate (600 mg 3 times daily), metronidazole (500 mg 3 times daily) and amoxicillin (500 mg 3 times daily) for 2 weeks. Then, all patients continued treatment with ranitidine (150 mg twice daily) for 8 weeks prior to the follow-up examination. Blood samples were collected before treatment for measurement of fasting gastrin and pepsinogen-I. RESULTS: Nine patients (45%) in the normacid group and 8 patients (40%) in the hyperacid group reported side effects. However, there were only 2 patients (10%) in each group who withdrew from the study due to intolerance of side-effects. There was no difference in the H. pylori eradication rate between the normacid and hyperacid groups (16/18, 88.9% vs. 15/18, 83.3%). CONCLUSIONS: Without co-administration of anti-secretary agents, intragastric acid is not a significant factor in the effectiveness of H. pylori eradication with bismuth-based triple therapy.