Despite being widely used for back pain and osteoarthritis pain, anti-depressant drugs have been found to be ineffective by a new review published in The BMJ. The findings show that while most clinical practice guidelines recommend anti-depressants for long term chronic back pain, hip, and knee osteoarthritis, supporting evidence is uncertain on the effectiveness.
To help clarify the knowledge gap in anti-depressant use for back and osteoarthritis pain, researchers analyzed published data from 33 randomized controlled trials involving more than 5,000 adults with low back or neck pain, sciatica, and hip or knee osteoarthritis. Although each trial was designed differently and were of varying quality, researchers were able to allow for them in their analysis.
Researchers set a difference of 10 points on a 0-to-100-point scale for pain or disability as the smallest worthwhile difference between groups for the analysis. This is a threshold commonly used in other studies of chronic pain.
It was found that serotonin-norepinephrine reuptake inhibitors (SNRIs) reduced back pain after three months. However, the effect was small. An average difference of 5.3 points on the pain scale was reported compared with placebo. This is such a small amount that it is unlikely to be considered clinically significant by most patients.
For osteoarthritis, researchers did find a slightly more substantial effect of SNRIs on pain after three months. With an average difference of 9.7 pain points, it was concluded that a practical effect could not be excluded.
For tricyclic anti-depressants (TCAs), evidence showed that they were not effective for back pain and related disability. It was concluded that tricyclic anti-depressants and SNRIs might reduce pain in people with sciatica, but the evidence was not certain enough to draw firm conclusions.
This study did have several limitations, which the researchers do acknowledge. These include the possibility of missing trials and being unable to explore a dose-response relation for most anti-depressants because of the low number of studies spread across six different classes of anti-depressants.
Even with these limitations, researchers believe their review can update the evidence for osteoarthritis, back pain, and sciatica and could help clinicians stop over-prescribing anti-depressants for chronic pain.
The researchers concluded, “Large, definitive randomized trials that are free of industry ties are urgently needed to resolve uncertainties about the efficacy of anti-depressants for sciatica and osteoarthritis highlighted by this review.”
Health experts call for more straightforward guidance to create a consistent approach for the use of anti-depressants for people with painful disorders. Even though there seems to be little use for anti-depressants in the field of pain, many patients still choose to try them for a small chance of a worthwhile reduction in pain.
However, this study shows that this is not the best option when dealing with painful disorders. Researchers argue that drug treatments “are largely ineffective for back pain and osteoarthritis and have the potential for serious harm. We need to work harder to help people with these disorders to live better with their pain without recourse to the prescription pad.”