Efficacy of 2-Week, Second-Line Helicobacter pylori Eradication Therapy Using Rabeprazole, Amoxicillin, and Metronidazole for the Japanese Population

Background: Following the failure of first-line Helicobacter pylori eradication therapy using a proton pump inhibitor, amoxicillin, and clarithromycin, second-line therapy is conducted for 1 week using metronidazole instead of clarithromycin in Japan. Recent studies indicate that metronidazole-containing therapy has a higher eradication rate with prolonged treatment duration, even with metronidazole resistance. The aim of this study was to reveal the efficacy of 2-week metronidazole-containing second-line therapy. Methods: Eighty-two consecutive outpatients who had failed in the first-line eradication therapy were enrolled and second-line therapy was initiated with 10 mg rabeprazole, 750 mg amoxicillin, and 250 mg metronidazole twice daily. After they had been screened by hematological examination 1 week after initiation, the treatment was continued for 2 weeks after initiation in patients without hematological abnormality. Cure was essentially confirmed by the urea breath test. Results: After one patient was lost, hematological examination showed elevated serum aminotransferase in 14 of 81 patients. Although it was mild without clinical issues, they were ethically excluded from this study. In the remaining 67 patients and the lost patient, the eradication rate with 2-week therapy was 65/68 (96%, 95% confidence interval: 88-98%) by intention to treat analysis and 65/65 (100%, 94-100%) by per protocol analysis. The main adverse event was soft stools (39%), and no serious adverse event was observed. Conclusion: This 2-week metronidazole-containing second-line therapy provides high efficacy in Japan where metronidazole resistance is rare.