Antidepressants are used to treat depression, anxiety, or both by correcting imbalances in brain chemistry. For people who have irritable bowel syndrome (IBS), doses much lower than those usually used to treat depression can also help relieve intestinal spasms and may relieve sensations of pain, bloating, and feeling like you are unable to pass a stool.

They may be used to treat chronic, unremitting abdominal pain that interferes with your daily activities. Here are some examples of antidepressants used to treat IBS. Your doctor may give you one that is not in this list.

• Amitriptyline hydrochloride
• Bupropion hydrochloride (Wellbutrin)
• Citalopram hydrobromide (Celexa)
• Fluoxetine hydrochloride (Prozac)
• Imipramine (Tofranil)
• Paroxetine hydrochloride (Paxil)
• Sertraline hydrochloride (Zoloft)
• Trazodone (Desyrel)
• Venlafaxine hydrochloride (Effexor)

For people who have IBS along with depression and anxiety, these medications may be used in doses that are usually used to treat depression or anxiety. Some antidepressants may worsen constipation; others may worsen diarrhea. You may start to feel better within 1 to 3 weeks of taking antidepressant medicine. But it can take as many as 6 to 8 weeks to see more improvement. If you have questions or concerns about your medicines, or if you do not notice any improvement by 3 weeks, talk to your doctor. See the topic Depression for more information.

FDA Advisories. The U.S. Food and Drug Administration (FDA) has issued:

• A warning on the antidepressants Paxil and Paxil CR (paroxetine) and birth defects. One new study showed that women who took Paxil during their first 12 weeks of pregnancy had a slightly higher chance of having a baby with birth defects.
• An advisory on antidepressant medicines and the risk of suicide. The FDA does not recommend that people stop using these medicines. Instead, a person taking antidepressants should be watched for warning signs of suicide. This is especially important at the beginning of treatment or when the doses are changed.

See Drug Reference for more information about these medications. (Drug Reference is not available in all systems.)