[121, 122] Concomitant therapy is the regimen containing nitroimidazole and additional clarithromycin-containing triple therapy. This regimen was proposed since it was unclear whether the improved H. pylori eradication rate of sequential therapy was achieved by sequential drug administration or additional use of antibiotics such as metronidazole, and the studies that showed high H. pylori Small molecule library order eradication rate by sequential therapy were heterogeneous.[123]

In a randomized study, 5 days of concomitant therapy had an 80.7% H. pylori eradication rate in intention-to-treat analysis, which was not statistically different from clarithromycin-containing triple therapy.[124] In addition, another study that compared sequential and concomitant therapies did not report any significant difference in H. pylori eradication rates between the two therapies.[125] Asia-Pacific guidelines recommend clarithromycin-containing triple therapy as a secondary regimen for H. pylori eradication in cases of eradication failure with metronidazole-containing primary regimen. These guidelines

cite a study with a see more 75% eradication rate from intention-to-treat analysis.[15, 126] Maastricht IV/Florence guidelines recommend a combination of PPI, amoxicillin, and fluoroquinolone in cases of eradication failure with bismuth-containing quadruple therapy.[39] However, fluoroquinolone-containing 上海皓元医药股份有限公司 triple therapy has limitations as a secondary regimen in Korea because the resistance to fluoroquinolone has increased dramatically in recent years and is currently at 30% or higher.[106, 127, 128] Rifabutin, which has an antibacterial action in an acidic environment

and has been used for atypical tuberculosis, can also be used for triple combination therapy.[129] A recent study compared rifabutin 300 mg-containing triple therapy and levofloxacin-containing triple therapy as tertiary regimens, and reported low eradication rates of 71.4% and 57.1%, respectively.[130] Considering the cost of the treatment, the side-effect of bone marrow suppression, and the potential increased resistance to Mycobacterium tuberculosis, rifabutin triple combination therapy should only be considered in cases of multi-eradication failure.[4] In cases of primary and secondary eradication failure, Asia-Pacific guidelines recommend testing for CYP2C19 polymorphism, and the Maastricht IV/Florence guidelines recommend testing for antibiotics resistance.