Alosetron: an effective treatment for diarrhea-predominant irritable bowel syndrome.

Serotonin (5-HT) is one of the key mediators of gut motility, secretion and sensation. Most 5-HT is localized in the gastrointestinal tract. Particularly important for gut function and regulation are the 5-HT(1P), 5-HT(3) and 5-HT(4) receptors. These receptors have been the focus of research evaluating the pathophysiologic mechanisms of irritable bowel syndrome (IBS) as well as targets for the development of novel agents to treat irritable bowel syndrome. Alosetron is one of three 5-HT(3) antagonists currently available. The other two, ondansetron and granisetron, are primarily used in the treatment of chemotherapy-induced nausea and vomiting. Alosetron, which slows gut transit, has been approved for the treatment of severe diarrhea-predominant IBS (IBS-D) in women. This review will examine the common, yet therapeutically challenging, disorder IBS, as well as the role of alosetron in the treatment of IBS-D.