Alosetron

Alosetron (GR 68755) is a Serotonin 5HT3-receptor antagonist that is used in treatment of irritable bowel syndrome.IC50 Value: Target: 5-HT ReceptorAlosetron has an antagonist action on the 5-HT3 receptors of the enteric nervous system of the gastrointestinal tract. While being a 5-HT3 antagonist like ondansetron, it is not classified or approved as an antiemetic. Since stimulation of 5-HT3 receptors is positively correlated with gastrointestinal motility, alosetron's 5-HT3 antagonism slows the movement of fecal matter through the large intestine, increasing the extent to which water is absorbed, and decreasing the moisture and volume of the remaining waste products. From Wikipedia.

References:
[1]. Alosetron: an effective treatment for diarrhea-predominant irritable bowel syndrome By Harris, Lucinda A.; Chang, Lin From Women's Health (2007), 3(1), 15-27.
[2]. Cremonini F, Nicandro JP, Atkinson V, Shringarpure R, Chuang E, Lembo A.Randomised clinical trial: alosetron improves quality of life and reduces restriction of daily activities in women with severe diarrhoea-predominant IBS.Aliment Pharmacol Ther. 2012 Sep;36(5):437-48. doi: 10.1111/j.1365-2036.2012.05208.x.
[3]. Lucak S.Irritable bowel syndrome and ischemic colitis: evidence supporting the increased use of alosetron.Therap Adv Gastroenterol. 2012 Jul;5(4):215-8.
[4]. Nicandro JP, Shin P, Chuang E.Evaluation of treatment continuation with alosetron by IBS-D severity criteria.Curr Med Res Opin. 2012 Mar;28(3):449-56.