Irritable bowel syndrome (IBS) is a common disorder characterized by recurrent abdominal pain and altered bowel habits, often accompanied by bloating. IBS is classified by its predominant bowel symptom: constipation (IBS-C), diarrhea (IBS-D), mixed type (IBS-M), or unclassified (IBS-U). Since the exact cause of IBS is unknown, the goal of treatment is symptom control. Some over-the-counter (OTC) products and prescription drugs for IBS are listed in Tables 1-4. The safety of these drugs during pregnancy and lactation is described in Table 5 (online only).

Ulcerative colitis (UC) and Crohn's disease (CD), referred to collectively as inflammatory bowel disease (IBD), are chronic immune-mediated inflammatory conditions. Guidelines for treatment of UC and CD have been updated in recent years

View Figure: Treatments for Irritable Bowel Syndrome (IBS) in Adults

The FDA has approved vedolizumab (Entyvio - Takeda), an intravenous integrin receptor antagonist, for treatment of moderate to severe ulcerative colitis or Crohn's disease in adults who have not responded to, lost response to, or cannot tolerate standard treatment. Natalizumab (Tysabri), another integrin receptor antagonist, has been available for several years for treatment of Crohn's disease and multiple sclerosis.

View the Comparison Chart: Some Drugs for Irritable Bowel Syndrome with Diarrhea (IBS-D)

View the Comparison Chart: Some Drugs for Irritable Bowel Syndrome with Constipation (IBS-C)

View the Comparison Chart: Some Drugs for Abdominal Pain in Irritable Bowel Syndrome (IBS)

Rifaximin (Xifaxan – Salix), a minimally absorbed oral antibiotic approved previously to treat travelers' diarrhea and to reduce the risk of recurrent hepatic encephalopathy, has now been approved by the FDA for treatment of irritable bowel syndrome with diarrhea (IBS-D). Eluxadoline (Viberzi – Actavis), a mu-opioid receptor agonist, was also recently approved for IBS-D and will be reviewed in a future issue.

The FDA has approved tenapanor (Ibsrela - Ardelyx), a sodium/hydrogen exchanger 3 (NHE3) inhibitor, for twice-daily oral treatment of irritable bowel syndrome with constipation (IBS-C) in adults. Tenapanor is the first NHE3 inhibitor to become available in the US.

Lubiprostone (Amitiza), which was previously approved for treatment of chronic idiopathic constipation in adults, has now also been approved in a lower dose for use in women with irritable bowel syndrome with constipation (IBS-C). Since tegaserod (Zelnorm) has been withdrawn from the market,2 lubiprostone is the only drug approved by the FDA for treatment of this common condition.