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Antidepressants are widely used to treat pain around the world. However, new research from the University of Sydney shows that they can hardly or not at all help and even cause damage to people with chronic back pain and osteoarthritis.

Back pain and knee osteoarthritis affect millions of people around the world and are the leading causes of disability. When first-line pain relievers like acetaminophen and ibuprofen don’t improve symptoms, many people are prescribed antidepressants for their pain. Most guidelines for clinical practice recommend antidepressants for long-term (chronic) back pain and osteoarthritis of the hip and knee. However, evidence for their application is uncertain.

The study published today in the BMJ examined the effectiveness and safety of antidepressants for the treatment of back pain and osteoarthritis compared to placebo. The authors hope that this study could help doctors and patients make more informed decisions about whether to treat chronic back pain and osteoarthritis pain with antidepressants.

“The use of antidepressants to treat people with chronic back pain and osteoarthritis is increasing around the world. However, prior to our work it was not clear whether antidepressants were pain relief or safe,” said senior author Dr. Giovanni Ferreira, postdoctoral fellow at the Institute of Musculoskeletal Health at the University of Sydney and the Sydney Local Health District and the University’s Faculty of Medicine and Health.

“We conducted a review of all randomized clinical trials evaluating the effectiveness of antidepressants in people with back pain or knee osteoarthritis and found that the antidepressants were either ineffective or had very little effect on back pain, which they likely did It was not seen as useful in most patients. In people with osteoarthritis, the effects were still minor but could potentially be considered worthwhile by some patients, “he said.

“It is worrying that some antidepressants significantly increase a person’s risk of suffering adverse events. Many people are treated with these drugs that may not help and potentially harm their pain.”

About the study:

The study was a systematic review and meta-analysis that included 33 randomized controlled trials involving more than 5,000 participants with back or neck pain, sciatica, or hip or knee osteoarthritis.

The studies tested six classes of antidepressants, including serotonin-norepinephrine reuptake inhibitors (SNRIs) and tricyclic antidepressants.

The study set a 10 point difference on a pain scale from 0 to 100 as the smallest worthwhile difference between groups, which is a common threshold in chronic pain studies.

Most of the clinical trials included in the review did not include patients with pain and depression. The results apply to patients treated with these drugs for their pain condition, not to depression in people with pain.

Main results:

  • SNRIs had a trivially small effect on back pain, reducing pain on the pain scale by only 5.3 out of 100 points compared to placebo after three months. It is unlikely that this amount would be considered clinically important by most patients.
  • After three months, SNRIs had a slightly stronger effect on osteoarthritis pain, with an average difference of 9.7 points on the pain scale compared to placebo. This amount is still small, but is close to the 10 point difference required for antidepressants to be considered useful by some patients.
  • Tricyclic antidepressants were ineffective on back pain and related disabilities. Tricyclic antidepressants and SNRIs have been shown to relieve pain in people with sciatica (leg pain associated with back pain), but the evidence wasn’t strong enough to draw definitive conclusions.
  • SNRI antidepressants significantly increased the risk for patients with adverse events. About two-thirds of patients taking this class of antidepressants had at least one adverse event, such as nausea.

Professor Andrew McLachlan, principal and dean of pharmacy at the University of Sydney and co-author of the study, urges those currently taking antidepressants for the treatment of back pain and osteoarthritis not to stop antidepressant treatment abruptly but to consult their doctor.

“This can lead to withdrawal effects that can be distressing and sometimes serious health problems. These withdrawal effects include dizziness, nausea, anxiety, restlessness, tremors, sweating, confusion and difficulty sleeping.”

Dr. Ferreira added, “More research is needed to remove uncertainties about the effectiveness of antidepressants for sciatica and osteoarthritis, which are highlighted in this review.”

Stick to supportive shoes if you have knee pain

More information:
Efficacy and safety of antidepressants for the treatment of back pain and osteoarthritis: systematic review and meta-analysis, BMJ (2021). DOI: 10.1136 / bmj.m4825 Provided by the University of Sydney

Quote: Do antidepressants help with chronic back pain and osteoarthritis? (2021, January 20) Retrieved January 20, 2021 from https://medicalxpress.com/news/2021-01-antidepressants-chronic-pain-osteoarthritis.html

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