Medication for Diarrhea-Predominant Irritable Bowel Syndrome (IBS-D)

There are several medication options that can relieve the symptoms of diarrhea-predominant irritable bowel syndrome (IBS-D), which include frequent, urgent bouts of loose, watery diarrhea, abdominal pain, and cramping. While irritable bowel syndrome (IBS) can also cause diarrhea, IBS-D is unique in that diarrhea is the central symptom of the condition.

While some medications used for IBS-D are used for the treatment of diarrhea due to a variety of causes, there are a few drugs specifically approved for IBS-D, as well as others that are used off-label.

Over-the-Counter Medications

If you have IBS-D, over-the-counter anti-diarrhea medications may be effective in relieving your symptoms. However, they can cause serious side effects. Only use these options under the direction of your healthcare provider:

Imodium (Loperamide)

An over-the-counter anti-diarrhea medication, Imodium is taken orally and is usually well-tolerated when used as directed. It works against diarrhea by decreasing the speed of intestinal contractions and the amount of fluid in the large intestine. This results in less urgency and firmer stool.

Overuse may cause constipation or a serious side effect called toxic megacolon, which is severe distension (widening) of the colon.

Pepto-Bismol, Kaopectate (Bismuth Subsalicylate)

Medications containing bismuth subsalicylate relieve diarrhea, stomach upset, and indigestion. This ingredient prevents diarrhea by reducing the amount of fluid and inflammation in the intestines. It may not be practical if you have prolonged bouts of diarrhea with your IBS-D because it is not recommended that you take it for longer than two consecutive days.

Prescription Medications

There are a number of prescription treatments that you can use to relieve your diarrhea in IBS-D. Some are specifically indicated for the condition and others are effective for a variety of problems.

FDA-approved medications for the treatment of IBS-D include:

Xifaxan

Xifaxan (rifaximin) reduces abdominal pain, episodes of diarrhea, and bloating with IBS-D. This antibiotic is not absorbed in the stomach, and its actions are thought to occur locally in the small intestine. It is typically well-tolerated and does not have a harmful impact on bacteria within the large intestine, a concern with some other antibiotics.

Viberzi

Viberzi (eluxadoline) reduces episodes of diarrhea and abdominal pain in IBS-D. It works on opioid receptors within your digestive system to regulate the speed of intestinal contractions, fluid secretion, and pain sensations, and it is labeled a controlled substance because there is a risk that it could become habit-forming. Viberzi has also been associated with pancreatitis in people without a gallbladder.

Lotrinex

Lotrinex (alosetron HCL) is approved for females with IBS-D who have not improved with conventional therapy. According to the manufacturer, it can cause severe constipation, bowel obstruction (blockage of the intestines) due to hard stools, toxic megacolon (life-threatening widening of the colon), and ischemic colitis (death of the colon due to a lack of blood supply).

Antispasmodics and Anticholinergics

Antispasmodic/anticholinergic medications are frequently prescribed for the relief of abdominal pain and cramping in a number of conditions. These drugs target and reduce acetylcholine, a neurotransmitter that stimulates the digestive system.

However, the American College of Gastroenterology (ACG) has recently come out against the use of antispasmotics in the treatment of IBS. Despite their widespread use, according to the ACG, there is limited evidence that antispasmotics effectively treat the symptoms of IBS. Most of the scientific research that previously supported their use is decades old and of poor quality.

Antispasmodics commonly prescribed for IBS include:

• Bentyl (dicyclomine)
• Anaspaz, Cystospaz, Levbid, Levsin (hyoscyamine)
• Buscopan (hyoscine butylbromide)

Antidepressants

Although commonly prescribed for the treatment of depression and anxiety, antidepressants can have beneficial effects on IBS-D symptoms. Tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs) may work to reduce symptoms of IBS-D through their action on neurotransmitters in the intestines.

The treatment of IBS-D symptoms is considered an off-label use for antidepressants, but they are commonly used because they can be effective and are generally well tolerated.

Bile Acid Binders

Based on pooled data from six studies, about 28% of people with IBS-D meet the criteria for a condition known as bile acid diarrhea (BAD) or bile acid malabsorption (BAM). When excess bile acids accumulate in the colon, it leads to an increase in colonic fluid secretions, which cause diarrhea.

Unfortunately, testing for BAM is extremely limited in the United States.

There is some evidence that a subset of people with IBS-D may benefit from the use of off-label bile acid binders. However, according to the ACG, there is not enough information yet to recommend these medications to everyone with IBS-D.

Bile acid binders sometimes used to treat IBS-D include:

• Questran (cholestyramine)
• WelChol (colesevelam)
• Colestid (colestipol)

On the Horizon

Given that there are few options for IBS-D treatment, there is a great deal of interest in new medications for this condition. Medications currently being investigated include:

• ORP-101, a novel chemical compound made by OrphoMed that is still being tested in clinical trials
• Ebastine, a histamine H1-receptor antagonist that is currently used to treat allergies but may also help ease IBS-related pain

In addition, researchers are also studying a biomarker-therapeutic combination, including a blood test to screen people with IBS-D for bile acid diarrhea so they can be treated with a bile acid binder. Research on EnteraGam, classified as a medical food by the FDA, is in the preliminary stages but may be promising in terms of offering a safe and potentially effective treatment option for IBS-D.

A Word From Verywell

It may take years for you and your healthcare providers to recognize that you have IBS-D, even if you have already been diagnosed with IBS. The medication treatment strategies can be a little different than for IBS, as you may need little or no medication for constipation, and you may need to take anti-diarrhea medications more frequently.

Be sure to take medications only as recommended to avoid side effects and adverse events that can occur with the overuse of anti-diarrhea medicine.