Irritable bowel syndrome (IBS) is a common disorder characterized by recurrent abdominal pain and altered bowel habits, often accompanied by bloating.IBS is classified according to the predominant bowel symptom as IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), mixed type (IBS-M), or unclassified (IBS-U). Alterations in the microbiome, stress responses, sensory and motor function of the gut, and host genetic factors may be contributing factors. Since the exact cause of IBS is unknown, the goal of treatment is symptom control.

View the Table: Safety of Drugs for IBS in Pregnancy and Lactation

The FDA has warned that eluxadoline (Viberzi – Allergan), a mu-opioid receptor agonist and delta-opioid receptor antagonist approved in 2015 for treatment of irritable bowel syndrome with diarrhea (IBS-D),1 should not be used in patients without a gallbladder because of an increased risk of serious pancreatitis.2

As of February 2017, the FDA had received reports of 118 cases of serious, nonfatal pancreatitis and 2 deaths associated with use of eluxadoline. Both deaths occurred in patients without a gallbladder who developed severe abdominal pain and vomiting shortly after taking the first dose. At least 48 of the cases occurred after only 1 or 2 doses of eluxadoline. Of the 68 patients whose gallbladder status was reported, 56 did not have a gallbladder. Most of the patients without a gallbladder (44/56) were taking the reduced dosage of eluxadoline recommended for such patients (75 mg once/day).

Patients considered at risk for pancreatitis were excluded from the two trials that led to approval of eluxadoline. One case of pancreatitis and 8 cases of abdominal pain with hepatic enzyme elevation associated with sphincter of Oddi spasm occurred with use of eluxadoline in the trials, all in patients without a gallbladder.3

According to the current label, eluxadoline is contraindicated in patients who abuse alcohol (including those who consume >3 servings of alcohol per day) and in those with known or suspected biliary duct, pancreatic duct, or GI tract obstruction, sphincter of Oddi disease or dysfunction, or severe hepatic impairment (Child-Pugh C). It is also contraindicated in those with a history of pancreatitis, structural pancreatic disease, or chronic or severe constipation.

Some alternatives to eluxadoline, which is only modestly more effective than placebo in relieving IBS-D symptoms, are the antidiarrheal loperamide (Imodium, and generics), the non-absorbed antibiotic rifaximin (Xifaxan), and the 5-HT₃ receptor antagonist alosetron (Lotronex, and generics). Taken as needed, loperamide can reduce postprandial urgency and stool frequency, but it does not improve global symptoms of IBS-D. Like eluxadoline, rifaximin has only been modestly effective in relieving symptoms. Because of concerns about severe constipation and ischemic colitis, alosetron should be used only in women with severe, chronic IBS-D that is unresponsive to other drugs.4

1. Eluxadoline (Viberzi) for irritable bowel syndrome with diarrhea. Med Lett Drugs Ther 2016; 58:4.
2. FDA Drug Safety Communication: FDA warns about increased risk of serious pancreatitis with irritable bowel drug Viberzi (eluxadoline) in patients without a gallbladder. Available at: www.fda.gov. Accessed April 13, 2017.
3. AJ Lembo et al. Eluxadoline for irritable bowel syndrome with diarrhea. N Engl J Med 2016; 374:242.
4. Drugs for irritable bowel syndrome. Med Lett Drugs Ther 2016; 58:121.

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Irritable bowel syndrome (IBS) is a common disorder characterized by chronic, intermittent abdominal pain or discomfort and altered bowel habits. It is subtyped according to the predominant bowel symptom as IBS with constipation (IBS-C), IBS with 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.

The FDA has approved eluxadoline (Viberzi – Actavis), a mu-opioid receptor agonist and delta-opioid receptor antagonist, for oral treatment of adults with irritable bowel syndrome with diarrhea (IBS-D).

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.

Irritable bowel syndrome (IBS) is a common disorder, occurring in up to 15% of the US population; it is 2-2.5 times more frequent in women than in men. IBS is characterized by chronic, intermittent abdominal pain or discomfort accompanied by altered bowel habits. Since the underlying mechanisms of disease remain unclear, management of IBS focuses on symptom control.

Fluvoxamine maleate, a selective serotonin reuptake inhibitor (SSRI) that has been available for many years in an immediate-release formulation (Luvox, and others) for treatment of obsessive-compulsive disorder (OCD) in children and adults, has now been approved by the FDA in an extended-release formulation (Luvox CR - Jazz Pharmaceuticals) for treatment of OCD and social anxiety disorder (SAD) in adults.

Irritable bowel syndrome (IBS) is a common disorder, occuring in about 15% of the US population; it is 2-3 times more frequent in women than in men. IBS is characterized by chronic abdominal pain or discomfort and altered bowel habits.

Tegaserod maleate (teg a ser' od; Zelnorm - Novartis), a serotonin derivative, has received FDA approval for short-term treatment of women with irritable bowel syndrome (IBS) whose primary symptom is constipation. Alosetron (Lotronex), which was withdrawn previously because of toxicity, will soon be available again for women with severe diarrhea-predominant IBS (Medical Letter 2002; 44:67).

The FDA recently announced that it will permit reintroduction of alosetron hydrochloride (Lotronex - GlaxoSmithKline) for treatment of irritable bowel syndrome (IBS). The drug was previously withdrawn from the market because of severe gastrointestinal toxicity. The reintroduced drug will have a 50% lower starting dose, a narrower indication and some other marketing restrictions (www.fda.gov/cder/drug/infopage/lotronex/lotronex.htm).