GI Motility Modifier, Bulking Polymer, and Herbal Medicine

Gastrointestinal dysmotility is one of the important pathophysiology in IBS. Trimebutine maleate is the most popular and has been commonly used for IBS to control abdominal pain after bowel habits. Trimebutine has dual action for GI motilities, so effective for not only constipation-predominant type but also diarrhea-predominant type of IBS. In some guidelines and reviews, the use of trimebutine is generally recommended. Polycarbophil calcium as a bulking polymer improves the symptoms either diarrhea or constipation. The efficacy of polycarbophil calcium has been proven in placebo-controlled RCTs. About dietary fiber for the efficacy of IBS, a systematic review and meta-analysis were investigated, the effectiveness of soluble fiber for IBS was proved, but the effectiveness of an insoluble fiber for IBS was limited. The evidence for herbal treatment, most of which is conducted by traditional Chinese medicine. Overall, the evidence level of these studies is low quality. In Japan, traditional Japanese medicines (Kampo agents) have been used for treating IBS, but the study of efficacy for IBS is limited. Keishi-ka-shakuyaku-to significantly improved abdominal pain of diarrhea-predominant IBS in RCT of Japan. High levels of RCTs are needed to investigate the efficacy of herbal medicine.