[Second-line eradication therapy for H. pylori infection].

The widespread use of eradication therapy for Helicobacter pylori has lead to an increase in antibiotic-resistant strains and the problem of retreatment in cases of eradication failure. Retreatment in cases of eradication failure has achieved relatively good results with regimens containing bismuth compounds and tetracyclines in the world, but consensus has not been reached in Japan and each institution has its own policy. An triple therapy consisted of proton pump inhibitor, amoxicillin and metronidazole has been reported to show a good cure rate as a second line therapy in Japan, but metronidazole has not been approved by the Japanese regulatory authority for use against bacterial infections, including H. pylori, despite its worldwide use as an antimicrobial agent in H. pylori eradication regimens.