Background: The combination of omeprazole with amoxycillin or clarithromycin is used as treatment against Helicobacter pylori. It seems likely that the antibacterial activity of the antibiotic may be improved by increasing gastric pH towards neutrality, and a twice daily regimen of omeprazole is probably needed.
Aim: To assess the effects of twice daily administration of omeprazole 20 and 40 mg.
Methods: Twelve duodenal ulcer patients in remission were randomized to receive in single-blind fashion either placebo, omeprazole 20 mg or omeprazole 40 mg twice daily (08.00 and 20.00 h). On the sixth day of dosing they underwent 24-h gastric pH-metry.
Results: Omeprazole 20 and 40 mg b.d. produced marked decreases (P < 0.001) of 24-h gastric acidity (pH 5.4 +/- 0.9 and pH 5.7 +/- 0.6, respectively, vs. a basal pH of 1.4 +/- 0.2) and kept gastric pH at levels higher than 3.0 for almost 24 h. Gastric pH was kept above 5.0 for about 18 h and above 6.0 for about 10 h, while the time spent above 7.0 did not exceed 3 h. There were no significant differences between the two omeprazole dosages at any pH threshold.
Conclusion: Omeprazole 20 mg b.d. is sufficient to render the gastric milieu as anacidic as possible in duodenal patients.