The Food and Drug Administration (FDA) has declared that those without a gallbladder should not use the drug, Viberzi. The medication is used to treat Irritable Bowel Syndrome (IBS) with diarrhea. IBS is essentially the contracting of the large intestine, which causes a number of symptoms, such as cramping, pain, and gas, among others. Millions of people suffer from IBS in the United States, but its underlying cause is unknown. Viberzi treats IBS by lowering the number of these contractions, which in turn relives symptoms and improves stool consistency.

However, instead of easing the symptoms of IBS in those without a gallbladder, Viberzi has potentially dangerous side effects. The FDA’s interest in the drug peaked when two gallbladder-less patients died from taking the medication. They died from different, yet interrelated causes. One of the two was afflicted with pancreatitis, or inflammation of the pancreas. The pancreas is an organ that produces hormones in order to help break down sugars going through the digestive system, and it is located proximate to the gallbladder. Coincidentally, those who were at high risk of developing pancreatitis were excluded from clinical trials.

The second of the two patients who died was stricken with spasms from their Sphincter of Oddi (Oddi) and died from complications. Oddi is a muscular valve that connects the duodenum to both the gallbladder and the pancreas and controls the flow of gastric juices and hormones between the two sections. During clinical trials, 8 cases of Oddi contractions were reported, and they were all in patients who did not have gallbladders. It is thought that the contractions of Oddi are the cause of pancreatitis, in this case. Patients who suffered from this were seemingly at a higher risk of developing the inflammation.

Pancreatitis is a common complication Viberzi users face, with 120 cases or deaths reported to the FDA. 118 cases of pancreatitis were reported to the FDA as of February 2017, in addition to the two aforementioned deaths. Of those 120, 68 reported “gallbladder status”, and of those 68, 56 did not have a gallbladder, which shows a strong correlation. Disturbingly, symptoms of pancreatitis, such as stomach pain and vomiting, developed in patients after only a dose or two of Viberzi.

Despite the fact that Viberzi’s label suggests patients without gallbladders should not take the drug, this idea seemingly was alleged to have not been placed at the forefront by its manufacturer, Allergen. Most patients just took a smaller dosage (75mg).

The FDA is working to address all safety concerns.