Objectives: This prospective study was designed to compare the efficacies of levofloxacin-containing and high-dose metronidazole-containing quadruple therapies after failure of standard triple therapies.
Methods: A total of 150 Helicobacter pylori-infected patients were enrolled in our study and randomly assigned to levofloxacin-containing quadruple therapy (EBTL group) (40 mg of esomeprazole twice daily, 300 mg of bismuth subcitrate four times daily, 500 mg of tetracycline four times daily and 500 mg of levofloxacin once daily for 10 days) (n = 76) or high-dose metronidazole-based quadruple therapy (EBTM group) (40 mg of esomeprazole twice daily, 300 mg of bismuth subcitrate four times daily, 500 mg of tetracycline four times daily and 500 mg of metronidazole four times daily for 10 days) (n = 74). Follow-up endoscopy or urea breath test was done 16 weeks later to assess the treatment response. Patients' responses, CYP2C19 genotypes and antibiotic resistances were also examined. All participants, caregivers and those assessing the outcomes were blinded to group assignment.
Results: Intention-to-treat analysis revealed that both groups showed similar eradication rates: EBTL, 78.9% (60/76) (95% CI 69.7%-88.1%) and EBTM, 79.7% (59/74) (95% CI 70.5%-88.7%) [risk ratio (RR) 0.97, 95% CI 0.44-2.14]. Per-protocol results were EBTL = 87.0% (60/69) (95% CI 79.4%-94.9%) and EBTM = 90.8% (59/65) (95% CI 83.8%-97.8%) (RR 0.68, 95% CI 0.23-2.0). We did not find significant differences in compliance (RR 0.5, 95% CI 0.54-2.3) and adverse events (RR 1.11, 95% CI 0.54-2.3) between the two groups. Logistic regression analysis showed that only compliance was an important predictor for eradication failure. CYP2C19 polymorphism did not influence the eradicating effect.
Conclusions: The 10 day bismuth quadruple therapies with high-dose metronidazole or levofloxacin were effective even in areas with high resistance. These two therapies were equally safe and tolerated. Besides this, the metronidazole-containing therapy was cheaper. So it is persuasive that high-dose metronidazole-containing quadruple therapy could be a good choice for second-line H. pylori eradication in areas with high resistance.