Efficacy and Safety of Serotonin Receptor Ligands in the Treatment of Irritable Bowel Syndrome: A Review

Background: Irritable bowel syndrome (IBS) is a chronic, recurrent bowel disorder with an unknown etiology, which is most likely multifactorial. Increased mucosal permeability, visceral hypersensitivity and activation status of intestinal mucosal immune cells cause changes in gastrointestinal (GI) motility, secretion and sensation observed in the course of IBS. Permanent, cumbersome symptoms, such as diarrhea, constipation and abdominal pain greatly lower the quality of life of IBS patients. On this basis, according to the Rome IV criteria, different forms of IBS can be distinguished. Objective: This article focuses on the role of serotonin system in the pathophysiology of IBS as a potential therapeutic target. We shortly describe several molecules, associated with serotonin receptors, mainly 5-HT3 receptor antagonists and 5-HT4 receptor agonists, that are used in the treatment of motility disorders and visceral pain in IBS patients. We summarize the findings obtained in the clinical trials and elaborate on the safety of the serotonin ligands. Although the majority of serotonin receptor ligands relieve global symptoms, there are also some adverse effects, which can be dangerous for patients. Results and Conclusion: We postulate that currently, among all serotonin-targeting compounds, ramosetron is the best treatment option for IBS-D patients, due to its exceptional efficacy in both genders as well as good tolerability. Whereas, tegaserod is highly recommended for IBS-C sufferers. Nevertheless, numerous studies on the new serotonin receptor ligands are conducted to ensure the delivery of novel compounds with improved efficacy and safety profiles.