A new quadruple therapy for Helicobacter pylori: influence of resistant strains on treatment outcome

Background: There have been no reports concerning the efficacy and safety o f a 1-week quadruple therapy regimen of omeprazole, amoxycillin, roxithromy cin and metronidazole for Helicobacter pylori infections and the impact of primary resistance on the eradication rate. Methods: One hundred and sixty-nine consecutive patients with peptic ulcer disease as well as gastritis with biopsy-proven H. pylori infection were en tered into an open study of omeprazole 20 mg o.m., amoxycillin 500 mg t.d.s ., roxithromycin 150 mg b.d., and metronidazole 250 mg t.d.s. Helicobacter pylori status was determined by urease test, histology and culture. Suscept ibility to amoxycillin, metronidazole and roxithromycin was determined by t he E-test. Results: H. pylori was eradicated in 155 out of 169 (92%; 95% CI 88-96%) by intention-to-treat analysis, and in 155 out of 163 (95%; 95% CI 92-98%) by per protocol analysis. The prevalence of primary resistance against amoxyc illin, roxithromycin and metronidazole was 2 out of 166 (1%), 16 out of 166 (10%) and 27 out of 166 (16%), respectively. H. pylori was eradicated in 2 5 out of 27 (93%) patients with metronidazole-resistant strains compared wi th 130 out of 136 (96%) in patients with metronidazole-sensitive strains of H. pylori. It was eradicated in 15 out of 16 (94%) patients with roxithrom ycin-resistant strains while in 140 out of 147 (95%) patients with roxithro mycin-sensitive strains of H. pylori, and in two out of two (100%) patients with amoxycillin-resistant stains compared with 153 out of 161 (95%) in pa tients with amoxycillin-sensitive strains. H. pylori was eradicated in thre e out of four (75%) patients with double resistance against metronidazole a nd roxithromycin compared with 152 out of 159 (96%) patients with sensitive strains to metronidazole and or roxithromycin. None of these differences w ere statistically significant. Severe side-effects were found in only one o ut of 169 patients-anaphylaxis due to penicillin. Conclusions: The 1-week quadruple therapy with omeprazole, amoxycillin, met ronidazole and roxithromycin was found to eradicate H. pylori in over 90% o f all patients. This regimen was also found to be beneficial for patients w ith pre-treatment resistant strains to metronidazole, roxithromycin or amox ycillin, and was observed to be safe and well-tolerated.