Drug Therapy of Irritable Bowel Syndrome

Bak, Young Tae

Abstract

Irritable bowel syndrome (IBS) is a chronic relapsing disorder of gastrointestinal function, the main features of which are abdominal pain or discomfort and an alteration of the bowel habit. Rome â…¡ criteria is the most recent international consensus definition for IBS. Rome â…¡ consensus provides working definitions for constipation-(C-IBS) and diarrhea-predominant (D-IBS) subgroups. Initial management begins with a detailed history taking, including a careful dietary history. The presence of obvious causative factors of stress should be identified. Therapeutic trials may include those of dietary fiber supplementation for C-IBS, dietary manipulation and/or antidiarrheal agents for D-IBS, and antispasmodics for prominent pain. Reassurance of the patient is vital in the initial management. Current approaches to the long-term management of IBS include dietary measures, fiber and bulking agents, antispasmodic agents, antidiarrheal agents, laxatives, psychotroic drugs, and psychological and behavioral therapy. Medications should be prescribed as required, rather than on a regular basis. For moderate or severe abdominal pain, antispasmodics and certain smooth muscle relaxants may be used. These types of drugs are ideally used for a short term during an exacerbation of symptoms. In resistant cases, low-dose antidepressants have been used to treat the abdominal pain of IBS. For diarrhea, loperamide can be used effectively on a p.r.n. basis. For constipation, an increase in dietary fiber and/or dietary fiber supplements should be continued in a long-term basis. If symptoms continue, osmotic laxatives can be tried. Anthraquinone laxatives such as aloe or senna should be avoided in long-term treatment.