Duration of the metronidazole-containing regimen for eradication of Helicobacter pylori infection in northern Japan.

Metronidazole is often used to eradicate clarithromycin-resistant Helicobacter pylori. The aim of this study was to determine the appropriate duration of metronidazole-containing treatment for the eradication of H. pylori infection in northern Japan. We enrolled 83 H. pylori-positive patients in whom first-line triple therapy consisting of a proton pump inhibitor, amoxicillin and clarithromycin had failed. Prior to the second-line therapy, patients underwent endoscopy to obtain H. pylori strains to test the susceptibility to antibiotics. Patients were administered lansoprazole (30 mg b.d.), amoxicillin (750 mg b.d.) and metronidazole (250 mg b.d.) for 5 or 7 days, and the treatment results were tested by (13)C-UBT. None of the isolated H. pylori strains was amoxicillin- or metronidazole-resistant. All the patients completed the regimen without major adverse effects. The eradication rate was 95.1% (39/41; 95% confidence interval [CI], 83.5-99.4%) in the 41 patients who were treated for 5 days and 95.2% (40/42; 95% CI, 83.8-99.4%) in the 42 patients treated for 7 days. The results suggest that 5 days could be a sufficient duration for triple therapy of lansoprazole, amoxicillin and metronidazole as a second-line H. pylori eradication therapy in areas where metronidazole-resistant strains are rare.