Paxil May Help Irritable Bowel Syndrome
<P>Antidepressant Has Strong Effect in Those Not Feeling Fit After Fiber</P>
Why would an antidepressant work in people who aren't depressed? Older tricyclic antidepressants are often used to treat irritable bowel syndrome. But newer antidepressants -- the SSRI class, like Paxil -- specifically act to increase the action of serotonin, a chemical messenger.
The drugs are designed to increase serotonin levels in the brain. But that's not the only place serotonin is found.
"Here's why I think Paxil works for irritable bowel: 95% of the serotonin in the body is in the intestine," Arnold says. "I think it is doing something to the nerves in the gastrointestinal tract."
Shaker notes that people with irritable bowel syndrome tend to have problems with the way sensations arise in the gut, the way these sensations travel through the nerves to the brain, and/or with the way the brain processes these signals. He agrees that Paxil and other SSRIs are likely to affect this process.
"In future, there may be objective tests to tell which irritable-bowel patients have neural processing problems," Shaker says.
Arnold suggests that many patients may benefit from SSRI antidepressants such as Paxil. Indeed, he and Shaker note that many doctors already prescribe the drug for selected irritable-bowel patients.
"If you've got irritable bowel syndrome and are not on a high-fiber diet, you should be," Arnold says. "If that doesn't work after six weeks, try a trial of Paxil. Understand we are not treating depression. But the drug is safe [when taken under medical supervision], and most patients will feel better."
Arnold and colleagues' study appears in the May issue of the American Journal of Gastroenterology.