Doubling the omeprazole dose (40 mg b.d. vs. 20 mg b.d.) in dual therapy with amoxycillin increases the cure rate of Helicobacter pylori infection in duodenal ulcer patients.

Background: Several studies have shown that dual therapy with omeprazole and amoxycillin may cure Helicobacter pylori infection. However, the optimum dose of omeprazole has still to be established.
Methods: An international, randomized, double-blind multicentre trial was conducted in patients with duodenal ulcers to compare the H. pylori cure rates obtained by dual therapy consisting of either omeprazole 20 mg b.d. plus amoxycillin 750 mg b.d. or omeprazole 40 mg b.d. plus amoxycillin 750 mg b.d. for 2 weeks. Dual therapy was followed by omeprazole 20 mg once daily for 2 weeks. Before entering the trial and 4 weeks after cessation of treatment H. pylori infection was assessed by histology and a 13C-urea breath test.
Results: 381 patients were randomized into the study, of whom 345 were evaluable for the all-patients-treated analysis of efficacy and 378 were valid for the evaluation of safety. Histology results showed that H. pylori infection was cured in 64 out 174 patients treated with omeprazole 20 mg b.d. plus amoxycillin and in 102 out of 171 patients treated with omeprazole 40 mg b.d. plus amoxycillin (37% vs. 60%; P < 0.001). Both treatment regimens were well tolerated, with adverse events reported by 29 (15.2%) and 35 patients (18.7%), respectively.
Conclusions: This study has shown that dual therapy with amoxycillin 750 mg b.d. and omeprazole 40 mg b.d. is superior to dual therapy with amoxycillin and omeprazole 20 mg b.d. in patients with H. pylori-positive duodenal ulcers. Thus, a true dose-response relationship exists between omeprazole and treatment success. However, a combination of omeprazole with two of amoxycillin, clarithromycin and nitroimidazole is a preferable alternative for routine clinical use.