Is There a Benefit to Prescribing Antidepressants for Chronic Back, Hip, or Knee Pain?
Patients with hip or knee pain from osteoarthritis or those with chronic back pain are unlikely to experience relief of their symptoms from taking antidepressants. Not only that, but they may also be harming themselves by taking these medications, according to a study from the University of Sydney.
Millions of people worldwide are affected by chronic back, hip, or knee pain, which are leading causes of disability. When first-line pain medications such as acetaminophen and ibuprofen fail to provide symptoms relief, many people are prescribed antidepressants for their pain, as recommended by some clinical practice guidelines. Yet evidence supporting their use is uncertain.
The new study, a systematic review and meta-analysis published in BMJ, investigated the efficacy and safety of antidepressants for the treatment of osteoarthritis pain in the hip or knee pain or for chronic back pain, including lumbar or cervical spine pain with or without radicular symptoms (sciatica). The goal: To provide clinicians and patients with information to help them make more informed decisions about whether to treat these types of pain with antidepressants.
Thirty-three randomized controlled trials with 5318 participants who had chronic back pain or pain from hip or knee osteoarthritis were included in the study. These trials had evaluated 6 classes of antidepressants, including serotonin-noradrenaline reuptake inhibitors (SNRIs) and tricyclic antidepressants.
The study authors set a difference of 10 points on a 0 to 100 scale for pain as the smallest worthwhile difference between groups, which is a common threshold in studies of chronic pain.
Among the key findings of the study were the following:
- SNRIs had a small effect on back pain, reducing pain by just 5.3 points out of 100 on the pain scale compared with placebo after 3 months. This amount is unlikely to be considered clinically important by most patients.
- SNRIs had a slighter stronger effect on osteoarthritis pain after 3 months, with an average difference of 9.7 points on the pain scale compared with placebo. This amount is still small, but close to the 10 point difference needed for antidepressants to be considered worthwhile by some patients.
- Tricyclic antidepressants were ineffective for back pain and related disability
- Tricyclic antidepressants and SNRIs might reduce pain in people with sciatica, but the evidence was not certain enough to draw any firm conclusions.
- SNRI antidepressants significantly increased the risk of patients experiencing an adverse event, with about two-thirds of patients taking this class of antidepressant experiencing at least 1 adverse event such as nausea.
Most of the clinical trials did not include patients with pain and depression. The findings apply to patients treated with these drugs for their pain condition, not depression in people living with pain.
The study authors said that more research is needed to resolve uncertainties about the efficacy of antidepressants for sciatica and osteoarthritis highlighted by this review article.
Ferreira GE, McLachlan AJ, Lin CC, et al. Efficacy and safety of antidepressants for the treatment of back pain and osteoarthritis: systematic review and meta-analysis. BMJ. 2021 Jan 20;372:m4825. doi: 10.1136/bmj.m4825.