Pharmacotherapy for IBS-D

Irritable bowel syndrome (IBS) is characterized by chronic and recurrent abdominal pain associated with defecation or a change in bowel habits. These problem are caused by complex and combined physiological factors such as serotonin (5-HT), bile acid, microbiota, low-grade mucosal inflammation, immune activation, intestinal permeability, and psychosocial factors. In accordance with the above pathophysiological factors, antispasmodic drugs, probiotics, loperamide, 5-HT3 receptor antagonists, bile acid sequestrants, and antidepressants have been utilized for pharmacotherapy in patients with diarrhea-dominant IBS (IBS-D). Furthermore, there are many randomized controlled trials that have shown 5-HT3 receptor antagonists (alosetron, ramosetron), a mixed opioid receptor acting drug (eluxadoline), and nonabsorbable antibiotics (rifaximin) are notably effective in improving abdominal pain and stool consistency in patients with IBS-D.