CLINICAL EFFICACY OF TRIPLE THERAPY IN HELICOBACTER-PYLORI-ASSOCIATED DUODENAL-ULCER

Objective: To evaluate a triple treatment regimen of colloidal bismuth subcitrate (CBS), metronidazole and tetracycline in eradicating metronidazole resistant Helicobacter pylori in patients with duodenal ulcer and to assess interaction between metronidazole and tetracycline against H. pylori in vitro. Design: Eighty-nine patients with H. pylori infection and duodenal ulcer disease were treated with CBS 120 mg four times daily for 4 weeks, metronidazole 400 mg three times daily and tetracycline 500 mg three times daily for the first week. H. pylori was cultured and susceptibility to metronidazole and tetracycline assessed before and 4 weeks after treatment. In vitro interaction between metronidazole and tetracycline against H. pylori was evaluated with a checkerboard technique. Results: The triple therapy healed duodenal ulcer in 90.7% (59 out of 65) of patients with metronidazole sensitive strains and 79.2% (19 out of 24) of those with resistant strains (P>0.05). H. pylori was eradicated in 92.3% (60 out of 65) of patients with metronidazole sensitive strains and in 62.5% (15 out of 24) with metronidazole resistant strains (P<0.001). Healing of duodenal ulcer and improvement of antral inflammation was associated with eradication of the organism. Side effects were negligible. Synergism was observed against seven (30.4%) of 23 strains tested. Conclusions: The triple therapy with CBS, metronidazole and tetracycline for 1 week is effective in eradicating H. pylori. Resistance to metronidazole reduces, although not completely, the efficacy of triple therapy. Evaluation of in vitro interaction between antimicrobials may be helpful in chosing multiple chemotherapy for eradicating H. pylori.