Concomitant therapy and hybrid therapy

Concomitant therapy and hybrid therapy were developed to improve the effcacy of empirical eradication therapy. Concomitant therapy is a regimen in which antimicrobial agent of clarithromycin-containing triple therapy and nitroimidazole are administrated at the same time. This therapy has strength in that it is as superior as sequential therapy to clarithromycin-containing triple therapy in the eradication rate and simplicity than sequential therapy. Therefore, it is currently recommended as a frst-line eradication therapy to replace conventional clarithromycincontaining triple therapy in many guidelines in the frst-line treatment of Helicobacter pylori infection. However, as antimicrobial resistance is gradually increasing worldwide, it is questionable whether the acceptable effcacy of concomitant therapy could be maintained in the future. By adding an antimicrobial agent, there is risk of using an unnecessary antimicrobial agent. This increases the need for antibiotic stewardship and increases the risk of microbiota dysbiosis. In addition, it is not well established how to choose rescue antimicrobial agent when frst-line concomitant therapy fails. Hybrid therapy is a regimen in which amoxicillin which is administrated in the frst half of sequential therapy is continuously administrated during the last half. Hybrid therapy also demonstrated favorable results along with reverse hybrid therapy, which is being studied recently, but the complexity of the regimen itself is a still unsolved problem.