FDA OKs Eluxadoline and Rifaximin for IBS With Diarrhea

May 27, 2015

The US Food and Drug Administration (FDA) today approved not one, but two separate drugs to give relief to adults with irritable bowel syndrome and diarrhea (IBS-D).

One of the drugs, eluxadoline (Viberzi, Actavis), has a new active ingredient that triggers receptors in the nervous system to reduce bowel contractions, the FDA said. Actavis described it in a news release as having mixed opioid receptor activity — it is a mu receptor agonist, a delta receptor antagonist, and a kappa receptor agonist.

The other drug, an antibacterial called rifaximin (Xifaxan, Salix Pharmaceuticals), was already indicated for travelers' diarrhea caused by noninvasive strains of Escherichia coli, and overt hepatic encephalopathy.

Between 10% and 15% of Americans experience IBS, the FDA said. IBS-D is a subtype of this disorder, in which a patient has loose or watery stools about one fourth of the time.

"For some people, IBS can be quite disabling, and no one medication works for all patients suffering from this gastrointestinal disorder," said Julie Beitz, MD, director of the Office of Drug Evaluation III in FDA's Center for Drug Evaluation and Research, in a news release. "The approval of two new therapies underscores the FDA's commitment to providing additional treatment options for IBS patients and their doctors."

Clinical trials for both drugs showed that they were more effective in reducing abdominal pain and improving stool consistency than a placebo.

Constipation, nausea, and abdominal pain were the most common adverse events reported for eluxadoline. The FDA said that the most serious risk posed by eluxadoline is spasm in the smooth muscle surrounding the end of the common bile and pancreatic ducts. Such spasms can lead to pancreatitis. Clinicians should not prescribe the drug to patients with a history of bile duct obstruction, pancreatitis, severe liver impairment, or severe constipation, or to those who drink more than three alcoholic beverages per day.

The most common adverse events for rifaximin include nausea and higher blood levels of a liver enzyme called alanine aminotransferase. Clinicians should exercise caution when prescribing rifaximin to patients with severe liver impairment or in combination with a P-glycoprotein inhibitor.

More information on today's FDA announcement is available on the agency website.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.