One-week versus two-week H₂-receptor antagonist in combination with amoxicillin and tinidazole for eradication of Helicobacter pylori infection

Background/Aims: Eradication regimens combining two antibiotics with a proton pump inhibitor have been studied intensively in Helicobacter pylori (H. pylori) infection; however, only a few reports have focused on the role of H₂-receptor antagonists (H₂-RAs) in eradication therapy. The mechanism involved in the synergy between antibiotics and H₂-RAs are still elusive. So we compared the efficacy of two regimens: a 1-week or 2-week course of highdose H₂-RA-based triple therapy in patients with H. pylori infection, and assessed the impact of primary resistance for metronidazole on the treatment outcome. Methodology: One hundred and twenty patients with peptic ulcers and nonulcer dyspepsia were randomly assigned to a one-week course of famotidine 40mg b.i.d., amoxicillin lg b.i.d. and tinidazole 500mg b.i.d. (FAT1 group; n=60) or a 2-week course of famotidine 40mg b.i.d., amoxicillin lg b.i.d. and tinidazole 500mg b.i.d. (FAT2 group; n=60). Upper endoscopy was performed prior to treatment and at least 4 weeks after completion of treatment and discontinuation of the antisecretory therapy. H. pylori status was assessed by biopsy urease test, histology and culture. Results: In the intention-to-treat analysis, eradication of H. pylori was achieved in 38 of 60 patients (63.3%; 95% CI: 51-76%) in the FAT1 group, compared to 48 of 60 patients (80%; 95% CI: 70-92%) in the FAT2 group (NS). In the per protocol analysis, eradication therapy was achieved in 38 of 54 patients (70.4%; 95% CI: 58-82%) in the FAT1 group and 48 of 53 patients (90.6%; 95% CI: 83-98%) in the FAT2 group (p<0.05). The overall eradication rates for strains susceptible and resistant to metronidazole were 79.7% (95% CI: 71-89%) vs. 60% (95% CI: 44-74%) in the intention-to-treat analysis (p=0.016) and 84% (95% CI: 76-92%) vs. 71.9% (95% CI: 56-88%) in the per protocol analysis (p=0.12). Seven patients in the FAT1 group and six patients in the FAT2 group available for follow-up reported adverse events (11.7% and 10% respectively) without necessity of discontinuation of the study medications. Serious adverse events were not observed. Conclusions: A 2-week course of high-dose H₂-RA-based triple therapy is well tolerated and sufficiently effective in eradicating H. pylori infection. Presence of metronidazole resistance has a negative impact on the treatment efficacy.