Do antidepressants help patients with back pain?
That depends on which study you read and what kind of back pain you have.
In a review of 10 studies on back pain and antidepressants published recently by the Cochrane Collaboration, an international organization that reviews medical studies, Australian researchers found no clear evidence that antidepressants are more effective than sugar pills in helping patients with low-back pain. The finding is somewhat perplexing because, as the Australian researchers themselves noted, there is evidence that antidepressants can help with other types of chronic pain.
The researchers' findings also conflict with recent guidelines issued by the American Pain Society, which does recommend antidepressants for back pain, said Dr. Roger Chou, director of the guideline program. But he cautioned in an e-mail that antidepressants are not recommended as the "first line" treatment for low back pain partly because they can have side effects and partly because the benefit of antidepressants for back pain is "small to moderate."
While some people may be surprised that antidepressants might alleviate pain, it actually makes biological sense, said Dr. Daniel Carr, a pain specialist at Javelin Pharmaceuticals, Inc. in Cambridge.
"Antidepressants don't help much with back pain that is caused by muscle spasms or by a spinal disc pressing on a nerve," he said.
The drugs may help with pain caused by nerve injury. Carr says there is "pretty good evidence" that the drugs can combat nerve pain from shingles or HIV, possibly by keeping the nerve from firing excessively.
Some antidepressants are more likely to help with back pain than others. The ones that help most are SNRIs, that is, drugs that increase levels of two neurotransmitters, serotonin and norepinephrine. Older antidepressants called tricyclics such as Elavil also help.
If your back pain persists more than a few weeks, it's wise to see a doctor to figure out the cause and to see if antidepressants might help. That's especially true if you have both back pain and depression, as many people do.
JUDY FOREMAN
E-mail health questions to foreman@globe.com. 