A common treatment for chronic back pain may not provide much soothing after all. A new review released Wednesday suggests that antidepressants on average provide little to no back pain relief, though they could have a modest benefit for osteoarthritis and sciatica.
Chronic pain can be an emotionally draining experience, so antidepressants are sometimes prescribed by doctors to help sufferers with their mental distress. But beyond their typical use, research has also suggested that antidepressants such as serotonin-norepinephrine reuptake inhibitors (SNRIs) can have an added pain-relief effect. How this exactly happens is still being studied, but it’s thought the same neurotransmitters that regulate mood (and that antidepressants help balance) also play a part in regulating our sensations of pain, especially pain caused by damaged nerves or a dysfunctional nervous system.
At least one antidepressant—the drug duloxetine, also known as Cymbalta—has been approved in the U.S. to treat chronic nerve pain and back pain. And organizations such as the American College of Physicians now recommend duloxetine for lower back pain as well. But according to the authors of this new paper, published in the BMJ on Wednesday, the overall effectiveness of antidepressants for treating pain is still uncertain.
Their review looked at data from 33 randomized and controlled clinical trials examining the use of antidepressants for chronic back pain as well as osteoarthritis of the hip and knees, including trials that hadn’t been included in previous reviews of the evidence, they wrote. These trials involved over 5,300 participants in total. The main outcome they looked at was a reduction in people’s reported score on a pain scale from 1 to 100, with any reduction 10 points or more following three months of treatment being considered a clinical improvement that patients would notice in their lives.
Altogether, the review found that the average pain reduction for SNRIs in treating lower back pain three months into treatment was only around five points. For osteoarthritis, the average reduction from SNRIs was just under 10 points, so more likely to be a meaningful improvement. Other evidence also suggested that tricyclic antidepressants, an older class of drug, had little effect on back pain, but that both tricyclic antidepressants and SNRIs might have a effect on treating pain from sciatica, a particular type of nerve pain that can affect the legs and back. However, the researchers were much less certain about the latter two findings, due to the limited data available.
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“Our findings show that antidepressants are largely ineffective for back pain, but may be beneficial for osteoarthritis and sciatica,” lead author Giovanni Ferreira, a researcher studying musculoskeletal Health at the University of Sydney in Australia, wrote in an email.
The findings don’t necessarily mean that no one should use these drugs for back pain. Chronic back pain is notoriously difficult to treat, and, for some patients, even the hope of a small benefit might be worth trying for. But antidepressants have side effects, and both doctors and patients should know upfront that the chances of significant improvement from using them are likely slim, Ferreira and his team noted. There are also other, non-medication options that patients can still try, such as physical therapy programs and exercise.
“If people are currently taking antidepressants for their back pain or osteoarthritis and they feel that it is helping them, we recommend that they continue the treatment,” he said. Those who aren’t benefiting from them should consult with their doctor before making any changes, though, since abruptly stopping their use can cause withdrawal symptoms like anxiety and insomnia.
Another important consideration brought up the authors is that much of the data they studied came from trials funded by the makers of the antidepressants being tested. Industry-funded trials are well known to paint a rosier picture of the evidence, so it’s still possible that even the benefits they found here might not be as big as they look.
“This should be taken into account when interpreting the findings from our review, particularly for osteoarthritis, where six out of eight trials were sponsored by pharmaceutical companies,” Ferreira said. “That is why we still need more trials, and these should ideally be conducted by independent investigators free of industry ties.”