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Pain relievers may block antidepressants

April 27, 2011 12:00:00 AM PDT
Last year doctors wrote 253 million prescriptions for antidepressants. While they can be very effective, they don't work for everyone. The problem may be over-the-counter pain relievers.

Antidepressants and aspirin are a common cocktail for people who suffer from pain and depression. But a new study suggests it's a bad mix.

The findings may explain why drugs like Prozac, Paxil, Wellbutrin and Celexa aren't effective for everyone.

"Trying to understand why antidepressants sometimes work and sometimes don't work has been a very important problem for many years," said Dr. Ian Cook, a psychiatrist at Ronald Reagan UCLA Medical Center.

Cook says the study shows SSRI antidepressants combined with pain relievers such as aspirin, ibuprofen and naproxen may block a key biochemical pathway in the brain.

"This would actually antagonize or interfere with the ability of antidepressant medicines to be clinically effective for some people," said Cook.

Scientists saw this effect in mice. Then they looked to see if the same thing could happen in humans.

In the study, patients who took Celexa experienced depressive symptoms like crying more often, decreased appetite, feeling down, about 55 percent of the time. And when they reported taking an anti-inflammatory also, those depressive symptoms went up.

"They might have more days of feeling depressed and sad, they might have more days of having sleep trouble or energy problems, or feeling unmotivated more often," said Cook.

Cook says the findings are too preliminary to suggest doctors change the way they treat depression. But based on this research it would be good for doctors to ask their patients about which pain relievers they take. And if patients continue to be unresponsive to SSRIs, Cook says, there other ways to treat depression.

"There are lots of options. People can get well, and if a medication doesn't work then they need to work closely with their doctor to figure out a different treatment," said Cook.