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 th erapy 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 ran domized to receive one of the following regimens: (i) RBC 400 mg, amoxycill in 1 g, clarithromycin 500 mg [RAC]; (ii) RBC 400 mg, metronidazole 400 mg, clarithromycin 500 mg [RMC]; (iii) RBC 400 mg, metronidazole 400 mg, tetra cycline 1 g [RMT] (all given twice daily for 1 week); or (iv) RBC 400 mg pl us clarithromycin 500 mg twice daily for 2 weeks [RC-2]. Endoscopy (rapid u rease test and culture) and C-13-urea breath test (UBT) were performed befo re randomization. Four weeks after finishing medication, the C-13-UBT was r epeated in all cases and endoscopy was offered to patients with peptic ulce rs. Results: Four hundred patients were randomized but in two (one in the RAC g roup and one in the RMC group) H, pylori infection was not confirmed. Succe ssful 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% [7 5-90%]) were comparable, with a trend favouring clarithromycin-containing t riple therapy regimens. Among 276 isolates tested for antibiotic sensitivit y, primary resistance to metronidazole, clarithromycin and amoxycillin was found in 56%, 2% and 0.4%, respectively, When given RMC or RMT, patients in fected by metronidazole-resistant H. pylori had success in eradicating H. p ylori similar to patients infected by metronidazole-sensitive H, pylori. Conclusion: One-week RBC triple therapy is effective in curing H. pylori in fection.