Effect of lansoprazole in mono-, dual-, or triple therapy on Helicobacter pylori eradication.

The effect of lansoprazole, in mono, dual, or triple therapy, on the eradication of Helicobacter pylori was reviewed. Lansoprazole has a cytotoxic action against this organism, the MIC being 2.56-5.25 micrograms/ml. In in vitro experiments, lansoprazole exerts direct action, i.e., antibacterial activity of lansoprazole against H. pylori and also inhibits urease activity. With antibiotics, this drug has a synergistic effect against H. pylori. In clinical studies, the eradication rate of H. pylori with lansoprazole is 0%-25% with monotherapy, 22%-33% with dual therapy (of AMPC), and 75%-82.4% with triple therapy with metronidazole and antibiotics. We inves-tigated the effect of lansoprazole on the eradication of H. pylori with dual therapy, the other agent being amoxicillin (AMPC). The eradication rate was 0% when 30 mg lansoprazole was employed as monotherapy, 33% for dual therapy with 30 mg lansoprazole and 1 g AMPC, and 71% for dual therapy with 60 mg lansoprazole and 1 g AMPC, the eradication rate with 60 mg lansoprazole and 1 g AMPC being significantly higher than that with the lower dose of lansoprazole. This result suggested that the greater acid suppression brought about by lansoprazole 60 mg enhances the action of AMPC, indicating that lansoprazole, when used with AMPC, is effective for eradication of H. pylori.