New options in Helicobacter pylori eradication: efficacy, resistance and synergy.

The eradication of Helicobacter pylori has become the focus of much attention since the first attempts at developing effective therapies some 10 years ago. This review focuses on ranitidine bismuth citrate (RBC), the first new drug to be introduced for use in the eradication of H. pylori. RBC when combined with clarithromycin gives consistently high eradication rates (above 80% intention-to-treat assessment in double-blind, international studies) as a simple dual therapy for 14 days or when combined with two antibiotics as a triple therapy for 7 days. RBC enhances the in vitro killing of H. pylori by antibiotics, such as clarithromycin, metronidazole or tetracycline, in a synergistic manner. This effect is seen even when the H. pylori strains are 'resistant' to the antibiotics. Such a synergistic effect probably explains the increased efficacy of RBC-clarithromycin dual therapies compared with clarithromycin dosed with acid-suppressive agents such as H2-receptor antagonists or proton-pump inhibitors.