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Irritable Bowel Syndrome (IBS) Health Center

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Treating Irritable Bowel Syndrome (IBS) With Constipation

Laxatives for IBS continued...

Laxatives work well for occasional constipation, but they don't treat all IBS symptoms such as stomach aches and bloating.

Also, some laxatives can be habit-forming and harmful in the long run.

In stimulant laxatives, the ingredient senna triggers muscles in the bowels to contract, moving stool through the bowel. Over time, the chemical can damage nerves in the colon wall. Eventually, these laxatives may stop working in people who take them regularly. Stimulant laxatives include Dulcolax, Senokot, castor oil, and the plant cascara sagrada.

Other laxatives, called osmotic laxatives, pull water back into the colon to soften stool, which makes the stool easier to pass. But research has found that they don't help relieve IBS symptoms other than constipation. In fact, they may actually worsen other symptoms. Side effects include diarrhea, dehydration, and bloating.

Unlike stimulant laxatives, osmotics are considered fairly safe for long-term use. Osmotic laxatives include Lactulose, which must be prescribed by a doctor, and Miralax which is available over the counter.

These types of medications "are fine for a little while, but if you find you need to stay on them, you really just need to make sure you've got the right diagnosis," says Waring. It's important to make sure symptoms aren't signs of another disease.

Prescription IBS Drugs

Amitiza is a drug that has been approved by the FDA to treat IBS with constipation in women. The FDA says the drug was not approved for men because studies have not fully demonstrated its effectiveness in men. Common side effects for Amitiza include nausea, diarrhea, and abdominal pain. 

Linzess is also approved for IBS with constipation as well. The drug is a capsule taken once daily on an empty stomach, at least 30 minutes before the first meal of the day. Linzess helps relieve constipation by helping bowel movements occur more often. It is not for use in those 17 years of age or younger. The most common side effect of Linzess is diarrhea.   

Doctors may use other prescription medications to help relieve some of the symptoms of IBS, such as constipation, diarrhea, or abdominal cramping.


Antidepressants for IBS

Your doctor may prescribe a low dose of antidepressants for IBS. This does not necessarily mean that you are depressed.

Antidepressants can block the brain's perception of pain in the gut, says Beth Schorr-Lesnick, MD, FACG, a gastroenterologist at Montefiore Medical Center in Bronx, N.Y.

There are different kinds of antidepressants and doctors may choose one or the other, depending on whether you suffer from constipation-predominant IBS or diarrhea-predominant IBS.

For IBS patients with constipation, Schorr-Lesnick will sometimes prescribe small doses of a SSRI (selective serotonin reuptake inhibitor) antidepressant, such as citalopram Celexa, escitalopram (Lexapro), fluoxetine (Prozac), paroxetine (Paxil), and sertraline (Zoloft). They do not usually cause constipation. Their side effects include nausea, loss of appetite, and diarrhea.

Other older antidepressants (called tricyclic antidepressants) tend to cause constipation. Doctors usually prescribe them for IBS patients with diarrhea. These drugs include amitriptyline (Elavil), nortriptyline (Pamelor), and desipramine (Norpramine). Other side effects of tricyclic antidepressants include dry mouth, drowsiness, and blurred vision.

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