ABSTRACT
Irritable bowel syndrome (IBS) is one of the most prevalent functional gastrointestinal disorders. It is a multi-factorial disorder due to abnormal gastrointestinal motility, low-grade inflammation, visceral hypersensitivity, and communication between the gut-brain axis. IBS is traditionally treated with dietary and lifestyle modifications, fiber supplementation, and psychological and pharmacological therapies. Diet therapy including the low FODMAP diet and excluding certain food constituents is often used. Antispasmodics plus stool consistency modifiers to treat the major symptoms and defecation are first-line drug treatments. 5-Hydroxytryptamine (5-HT) receptors in the gastrointestinal tract, particularly 5-HT3 and 5-HT4 receptors are involved not only in modulating gut motility but in visceral sensory pathways. Drugs that act on both receptor classes appear to reduce visceral sensitivity and have inhibitory effects on motor activity in the distal intestine. 5-HT4 agonists may improve constipation-predominant IBS by normalizing bowel habits and thereby reduce abdominal pain. IBS continues to be a therapeutic challenge because of its diverse symptomatology and lack of a single pathophysiological target for drug intervention.