A pilot study of the effect of daikenchuto on rectal sensation in patients with irritable bowel syndrome

Background/Aims Daikenchuto (TU 100), a botanical agent that modulates gastrointestinal nerves, is used in the treatment of motility and functional disorders. Our aim was to study the effects of TU-100 on rectal compliance and sensation in patients with irritable bowel syndrome (IBS). Methods In 20 patients per treatment arm, we conducted a single-center, randomized, parallel-group, double-blind, placebo-controlled, singledose pharmacodynamics study evaluating the effects of TU-100, 15 g (5 g t.i.d. [means 3 times a day]), for 14-16 consecutive days on rectal compliance and rectal sensation (thresholds and sensation ratings), all measured at baseline and on the last day of medication treatment. The primary endpoint was rectal sensation thresholds and sensation ratings in response to balloon distension at 32 mmHg. Secondary endpoints were rectal compliance, sensation thresholds, ratings and tone (fasting and postprandial), bowel pattern, abdominal pain (average and worst severity) and bloating scores, IBS quality of life and safety profile. Results Rectal sensation ratings post-treatment were significantly associated with baseline (pre-treatment) ratings and with level of anxiety or stress recorded at the time of the sensation testing. There were no effects of TU-100 treatment on rectal sensation ratings, sensation thresholds, rectal fasting or postprandial tone, rectal compliance, bowel function, abdominal pain or bloating scores, or IBS quality of life. Conclusions TU-100 did not significantly affect rectal compliance and sensation in patients with IBS in this study.