A double-blind, randomized, placebo-controlled dose-ranging study to evaluate the efficacy of alosetron in the treatment of irritable bowel syndrome

Aliment Pharmacol Ther. 2000 Jan;14(1):23-34. doi: 10.1046/j.1365-2036.2000.00684.x.


Background: Irritable bowel syndrome is a common gastrointestinal disorder characterized by abdominal pain and discomfort and altered bowel habit. Antagonism at the 5-HT3 receptor may be of benefit in the treatment of irritable bowel syndrome.

Aims: To evaluate the effect of 12 weeks of treatment with alosetron, a 5-HT3 receptor antagonist at doses of 0.1 mg b.d., 0.5 mg b.d. and 2 mg b.d. in irritable bowel syndrome patients.

Methods: A double-blind, placebo-controlled, parallel-group study with a 2-week screening and a 12-week treatment period was conducted. A total of 462 patients (335 female) recorded details of the severity of their abdominal pain, and bowel function daily on a diary card throughout the study. At monthly clinic visits patients recorded the severity of their abdominal pain/discomfort and diarrhoea on a visual analogue scale.

Results: In the total population and in the female subpopulation (but not in males) alosetron 2 mg b.d. significantly increased the proportion of pain-free days and decreased the visual analogue scale score for diarrhoea compared with placebo. Alosetron at doses of 0.5 mg b.d. and 2 mg b.d. led to a significant hardening of stool, and a reduction in stool frequency in the total population.

Conclusion: Alosetron at a dose of 2 mg b.d. is an effective treatment for female patients with irritable bowel syndrome.

Publication types

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

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Carbolines / administration & dosage
  • Carbolines / adverse effects
  • Carbolines / therapeutic use*
  • Colonic Diseases, Functional / drug therapy*
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pain / etiology
  • Pain / prevention & control
  • Pain Measurement
  • Receptors, Serotonin / drug effects*
  • Receptors, Serotonin, 5-HT3
  • Serotonin Antagonists / administration & dosage
  • Serotonin Antagonists / adverse effects
  • Serotonin Antagonists / therapeutic use*
  • Sex Characteristics
  • Time Factors


  • Carbolines
  • Receptors, Serotonin
  • Receptors, Serotonin, 5-HT3
  • Serotonin Antagonists
  • alosetron