Medications

Medicine may be used along with lifestyle changes to manage symptoms of irritable bowel syndrome (IBS).

The goal of medicine treatment is to relieve your symptoms enough to prevent them from interfering with your daily activities, because it may not be possible to eliminate your symptoms. Medicines may be prescribed to treat moderate to severe pain, diarrhea, or constipation that does not respond to home treatment. No single medicine has been shown to be effective in relieving IBS over the long term.

Medication Choices

In most cases, the choice of medicine is based on your most troublesome symptom. For example, if diarrhea is the most bothersome symptom, using antidiarrheals or anticholinergics may be helpful.

For diarrhea

Medicines that may be used to treat severe diarrhea that does not improve with home treatment include:

• Antidiarrheals, including diphenoxylate (such as Lomotil) and loperamide (such as Imodium), which slow intestinal movements.
• Bile acid binding agents, including cholestyramine (such as Questran), which prevent bile acids from stimulating the colon, slowing the passage of stools and relieving diarrhea.
• Alosetron (Lotronex), which is used for some women who have severe diarrhea and who have not responded to other treatments. This medicine slows the movement of stools through the bowels.

For constipation

There are many medicines for severe constipation that does not improve with home treatment. Most of these medicines are available without a prescription and are okay to take once in awhile. Check with your doctor before you use any of these medicines every day for constipation. Medicines for constipation include:

• Lubiprostone (Amitiza), which works by increasing the amount of fluid in your intestines, making it easier for stool to pass.
• Osmotic laxatives (such as Milk of Magnesia and nonabsorbable sugars such as lactulose), which work by holding fluids in the intestine and drawing fluids into the intestine from other tissue and blood vessels. This extra fluid in the intestines makes the stool softer and easier to pass.
• Polyethylene glycol (such as MiraLax), which helps the stool hold on to more water, making it softer and easier to pass.
• Stimulant laxatives (such as Senokot), which speed up how fast stool moves through the intestines by irritating the lining of the intestines.

For pain and cramping

The following medicines may be used for long-term pain and cramping:

• Anticholinergics (antispasmodics), including dicyclomine (Bentyl), which help prevent or relieve painful cramping spasms in the intestines
• Antidepressants, including desipramine (such as Norpramin), which in low doses can help with pain caused by IBS

For anxiety or depression

The following medicines may be used if your IBS causes you to have anxiety or depression:

• Antidepressants, including fluoxetine (such as Prozac), which are especially helpful if you have depression and IBS
• Antianxiety agents, including diazepam (such as Valium), which can be used short-term to help with anxiety if it makes your IBS symptoms worse

What To Think About

Few medicines have proven consistently helpful and all medicines have side effects, so medicine should be used for specific symptoms that disrupt your normal daily activities.

If you also have another illness, such as depression, that triggers symptoms of irritable bowel syndrome, medicine for that illness may be needed.

Alosetron, a medicine that decreases abdominal sensitivity, has been shown to relieve symptoms in some women who have severe diarrhea and who have not responded to other treatments. Although this medicine was previously removed from the market when its use was shown to contribute to ischemic bowel disease (which occurs when there is not enough blood flowing to the intestines), the U.S. Food and Drug Administration (FDA) reapproved alosetron for limited use in IBS. Specific guidelines for the use of alosetron require health professionals prescribing it to sign a certificate and patients to sign a consent form.