Clarithromycin Versus Metronidazole as First-line Helicobacter pylori Eradication A Multicenter, Prospective, Randomized Controlled Study in Japan

Background:Helicobacter pylori eradication rates achieved with a first-line regimen of clarithromycin (CLR) combined with amoxicillin (AMX) and a proton pump inhibitor have recently fallen to 80% because of the increasing incidence of CLR resistance in Japan. This randomized multicenter trial aimed to compare the eradication success of 2 first-line triple therapy regimens: rabeprazole, amoxicillin, and clarithromycin (RAC) versus rabeprazole, amoxicillin, and metronidazole (RAM).Methods:A total of 124 consecutive patients infected with H. pylori were randomized into one of two 7-day therapeutic regimens: RAC (n=60) or RAM (n=64). Eradication was confirmed by the C-13-urea breath test. Adverse effects were also assessed.Results:Intention-to-treat and per protocol H. pylori eradication rates were 73.3%/77.2% in the RAC group and 90.6%/93.5% in the RAM group. The eradication rate of RAM therapy was significantly higher than that of RAC therapy. CLR, metronidazole, and AMX resistance was found in 36.2%, 2.1%, and 0% of patients, respectively. In addition, no relevant differences in adverse effects were observed.Conclusions:Metronidazole-based therapy (RAM) was superior to standard CLR-based therapy (RAC) for first-line H. pylori eradication. This reflects the progressive increase in CLR resistance observed in Japan.