Viberzi (eluxadoline) is a medication approved by the U.S. Food and Drug Administration (FDA) for the treatment of diarrhea-predominant IBS (IBS-D) in adults. Viberzi was designed to act locally on the digestive tract to help control diarrhea and alleviate abdominal pain caused by the disease.

While doctors still don't fully understand what causes the recurrent symptoms of IBS (including abdominal pain, bloating, gas, diarrhea, or constipation), Viberzi is able to provide relief to sufferers who don't respond to traditional anti-diarrheal agents.

How Viberzi Works

Viberzi is available by prescription and designed to be taken by mouth, twice daily, with food. It comes in both a 75-milligram and 100-milligram film-coated tablet.

Viberzi works by activating or impeding various opioid receptors in the digestive tract. These are the receptors involved in gut motility, pain sensation, and the secretion of intestinal fluids. Viberzi is unique in that it stimulates two types of receptor and inhibits another, providing relief without constipation.

These receptors each have different and unique functions:

Mu receptors are responsible for gut motility (the contraction of gastrointestinal muscles).
Kappa receptors inhibit colon contractions.
Delta receptors are associated intestinal secretions.

The addition of a delta receptor antagonist is key to avoiding constipation seen with other drugs such as Imodium (loperamide) and Lomotil (atropine/diphenoxylate) which only affect the mu and kappa receptors.

The FDA approved Viberzi based on two Phase III clinical trials which concluded that the drug offered modest improvement in the frequency and urgency of bowel movements and a modest improvement in abdominal pain and stool consistency.

Drug Side Effects

The side effects of Viberzi are typically gastrointestinal in nature but may also affect other systems due to the opioid effects. In some cases, the symptoms of the drug may trigger the very same ones experienced with IBS. Among some of the more common side effects:

Nausea
Abdominal pain
Upper respiratory tract infection
Vomiting
Runny or stuffy nose
Bloating
Bronchitis
Dizziness
Gas
Rash
Fatigue

The opioid effect can, in rare cases, affect the sphincter of Oddi (the valve while regulates the flow of bile and pancreatic fluid into the intestines). If this happens, pancreatitis can develop.

As such, Viberzi cannot be prescribed to persons who do not have a gallbladder (the organ that produces bile) or who have pancreatitis, liver impairment, a bile duct obstruction, or severe constipation. Hospitalization and death have been reported in persons without a gallbladder who took as few as two doses of Viberzi.

It should also be avoided in persons who drink more than three alcoholic beverages per day.

An opioid drug, Viberzi has the potential for abuse and/or dependence. It should only be used under the supervision of a doctor. While the effects are far less profound than Oxycontin (oxycodone), it can cause euphoria if abused and lead to opioid dependence.