Cilansetron in the treatment of diarrhea-predominant irritable bowel syndrome?

Information on the 5-hydroxytryptamine type 3 receptor antagonist cilansetron is scarce and most studies have only been published in abstract form. Results from preclinical and two dose-finding studies have suggested that cilansetron could be effective in the treatment of patients with diarrhea-predominant irritable bowel syndrome. Two large efficacy and safety trials extending over 3 and 6 months revealed a superiority of cilansetron 2 mg orally three-times daily over placebo reflected by numbers needed to treat of 4.8 and 5.6, respectively, for the parameter proportion of patients reporting adequate symptom relief. Dose-ranging studies showed no dose-response relationship. Cilansetron tended to induce constipation but, apart from transient ischemic colitis in four out of 1484 cases, no serious adverse effects were observed. Further trials are underway to fully determine the role of cilansetron in the treatment of diarrhea-predominant irritable bowel syndrome.