Pharmacologic Treatment Options for IBS With Constipation

Pramodini B. Kale-Pradhan, BS, PharmD; Sheila M. Wilhelm, PharmD


January 11, 2008

In This Article


Irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal (GI) system typified by abdominal pain or discomfort and altered bowel habits, ie, diarrhea, constipation, or alternation of the two. IBS affects women more often than men, and has an estimated prevalence of 10% to 15%.[1]

The pathophysiologic basis for IBS has not been fully elucidated. It has been shown that patients with IBS have an exaggerated response to GI contents, including greater motility of the sigmoid colon and a lower threshold to visceral pain compared with controls.[2] It is thought that neurotransmitters in the gut, such as serotonin, cholecystokinin, and dopamine, may play a role in IBS, and therefore they have been targets of pharmacologic therapy. Other approaches to therapy have included targeting GI smooth muscle with relaxants and antispasmodics, as well as holistic approaches which include dietary and lifestyle modifications and complementary and alternative therapies.

Recently, tegaserod (Zelnorm), a selective serotonin type 4 receptor (5HT4) agonist and the only agent approved for the treatment of constipation-predominant IBS (C-IBS), was withdrawn from the market due to potential cardiac adverse effects.[3] Tegaserod is now available only on a restricted basis, called the "treatment IND" program.[4] Therefore, it is important to be familiar with alternative treatment options for C-IBS, especially those available without a prescription.

In addition, there are a number of nonpharmacologic modalities available to treat C-IBS. Because it is a chronic functional disorder, therapy should begin with lifestyle modifications that should continue throughout the course of the disorder.[5] Dietary modifications such as the avoidance or moderation of patient-specific triggers, as well as adequate fiber and fluid intake, can decrease constipation. Avoidance of beans, cabbage, broccoli, and cauliflower may reduce IBS symptoms such as bloating and flatulence. Additionally, uncontrolled studies have found that exercise is associated with improved outcomes.


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