Ramosetron Reduces Symptoms of Irritable Bowel Syndrome With Diarrhea and Improves Quality of Life in Women

Gastroenterology. 2016 Feb;150(2):358-66.e8. doi: 10.1053/j.gastro.2015.10.047. Epub 2015 Nov 6.


Background & aims: Previous studies have indicated that serotonin-3-receptor antagonists might have a sex-specific effect in patients with irritable bowel syndrome with diarrhea (IBS-D). Alosetron has been approved for the treatment of only women, and ramosetron has been approved for the treatment for only men. We performed a randomized, placebo-controlled, phase 3 study to determine whether ramosetron reduces symptoms of IBS-D in women.

Methods: We performed a prospective study of 576 female outpatients with IBS-D (according to the Rome III criteria), from February 2013 through February 2014, at 70 academic Gastroenterology Departments in Japan. After a 1-week baseline period, subjects received either 2.5 μg ramosetron (n = 292) or placebo (n = 284) once daily for 12 weeks. Primary end points were the monthly rates of response for relief from overall IBS symptoms and increased stool consistency at the last evaluation point. Quality of life (QOL) also was quantified.

Results: A significantly higher proportion of patients given ramosetron reported global improvement (50.7%; 95% confidence interval [CI], 44.8-56.6) than patients given placebo (32.0%; 95% CI, 26.7-37.8)--a difference of 18.6% (95% CI, 10.7-26.5; P < .001). The relative risk was 1.58 (95% CI, 1.29-1.94) and the number needed to treat was 6 (95% CI, 4-10). A significantly higher proportion of patients in the ramosetron group reported increased stool consistency (40.8%; 95% CI, 35.1%-46.6%) than in the placebo group (24.3%; 95% CI, 19.4%-29.7%)--a difference of 16.5% (95% CI, 8.9%-24.0%; P < .001). Patients receiving ramosetron had significant reductions in abdominal pain and discomfort (P = .001) and greater improvement in QOL (P = .002) compared with placebo. Ramosetron induced constipation in 11.0% of patients.

Conclusions: In a randomized, placebo-controlled study of 576 women with IBS-D, 2.5 μg ramosetron per day reduced symptoms and increased stool consistency and QOL. Clinicaltrials.gov no: NCT01870895.

Keywords: 5-HT; 5-Hydroxytryptamine-3–Receptor Antagonist; Abdominal Pain; Discomfort.

Publication types

  • Clinical Trial, Phase III
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Benzimidazoles / adverse effects
  • Benzimidazoles / therapeutic use*
  • Constipation / chemically induced
  • Diarrhea / diagnosis
  • Diarrhea / drug therapy*
  • Diarrhea / psychology
  • Female
  • Gastrointestinal Agents / adverse effects
  • Gastrointestinal Agents / therapeutic use*
  • Humans
  • Irritable Bowel Syndrome / diagnosis
  • Irritable Bowel Syndrome / drug therapy*
  • Irritable Bowel Syndrome / psychology
  • Japan
  • Middle Aged
  • Prospective Studies
  • Quality of Life*
  • Risk Factors
  • Serotonin 5-HT3 Receptor Antagonists / adverse effects
  • Serotonin 5-HT3 Receptor Antagonists / therapeutic use*
  • Sex Factors
  • Time Factors
  • Treatment Outcome
  • Young Adult


  • Benzimidazoles
  • Gastrointestinal Agents
  • Serotonin 5-HT3 Receptor Antagonists
  • ramosetron

Associated data

  • ClinicalTrials.gov/NCT01870895