Background : The high prevalence of Helicobacter pylori resistance to metronidazole demands treatments more effective than standard bismuth-based triple therapy against these strains.

Aim : To evaluate the H. pylori eradication rate in both metronidazole-sensitive and -resistant strains following quadruple therapy using single-triple capsules of bismuth biskalcitrate, metronidazole and tetracycline, given with omeprazole.

Methods : One hundred and seventy valid patients with duodenal ulcer, gastric ulcer or non-ulcer dyspepsia were treated in eight centres located in five countries. H. pylori was confirmed at baseline using 13C-urea breath test, histology and/or culture. Patients received three single-triple capsules q.i.d. and omeprazole, 20 mg b.d., for 10 days. Each capsule contained bismuth biskalcitrate, 140 mg (as 40 mg Bi2O3 equivalent), metronidazole, 125 mg, and tetracycline, 125 mg. 13C-Urea breath test was repeated at least 4 and 8 weeks post-treatment.

Results : Overall eradication rates were 93% (158/170) by modified intention-to-treat analysis and 97% (142/146) by per protocol analysis. Eradication rates were 93% (40/43) and 95% (38/40) for strains resistant to metronidazole and 95% (82/86) and 99% (75/76) for strains sensitive to metronidazole by modified intention-to-treat and per protocol analysis, respectively.

Conclusion : This omeprazole–bismuth biskalcitrate–metronidazole–tetracycline 10-day regimen is a very effective and well-tolerated treatment, which overcomes metronidazole resistance.