One-week ranitidine bismuth citrate in combinations with metronidazole, amoxycillin and clarithromycin in the treatment of Helicobacter pylori infection:: the RBC-MACH study

Background: We have previously shown that ranitidine bismuth citrate (RBC)-based triple therapy is comparable to proton pump inhibitor-based triple therapy in eradicating Helicobacter pylori infection. Aim: To test the efficacy of different combinations of antimicrobials with RBC in the treatment of H. pylori infection. Methods: Dyspeptic patients with H, pylori infection were prospectively randomized to receive one of the following regimens: (i) RBC 400 mg, amoxycillin 1 g, clarithromycin 500 mg [RAC]; (ii) RBC 400 mg, metronidazole 400 mg, clarithromycin 500 mg [RMC]; (iii) RBC 400 mg, metronidazole 400 mg, tetracycline 1 g [RMT] (all given twice daily for 1 week); or (iv) RBC 400 mg plus clarithromycin 500 mg twice daily for 2 weeks [RC-2]. Endoscopy (rapid urease test and culture) and C-13-urea breath test (UBT) were performed before randomization. Four weeks after finishing medication, the C-13-UBT was repeated in all cases and endoscopy was offered to patients with peptic ulcers. Results: Four hundred patients were randomized but in two (one in the RAC group and one in the RMC group) H, pylori infection was not confirmed. Successful eradication of H, pylori (intention-to-treat analysis and 95% CI) of RAC (86% [79-93%]), RMC (90% [84-96%]), RMT (79% [71-87%]) and RC-2 (82% [75-90%]) were comparable, with a trend favouring clarithromycin-containing triple therapy regimens. Among 276 isolates tested for antibiotic sensitivity, primary resistance to metronidazole, clarithromycin and amoxycillin was found in 56%, 2% and 0.4%, respectively, When given RMC or RMT, patients infected by metronidazole-resistant H. pylori had success in eradicating H. pylori similar to patients infected by metronidazole-sensitive H, pylori. Conclusion: One-week RBC triple therapy is effective in curing H. pylori infection.