New research has found that some antidepressants may be effective in treating some chronic pain conditions, but there is a lack of solid evidence on the effectiveness of others.
Many people are unaware that some antidepressants (medications used to treat people living with depression) are also prescribed to treat certain chronic pain conditions.
Chronic pain affects between a third and a half of the UK population. Treatment of chronic pain is often suboptimal, with commonly used medications having limited or unknown benefits, and sometimes harmful side effects. Antidepressants are prescribed to help manage chronic pain, when the affected person does not have a mood disorder such as depression. Their use is increasing with time.
An international team of researchers, including academics from the University of Warwick, found that some classes of antidepressants were effective in treating some pain conditions in adults, but others were either ineffective, or the effectiveness was unknown.
Published in BMJThe study reviewed the safety and efficacy of antidepressants in the treatment of chronic pain, and for the first time, brings together all existing evidence in one document.
The researchers concluded that the results show that clinicians need to consider all the evidence before deciding to prescribe antidepressants for chronic pain management.
Antidepressants have a role in helping people living with chronic pain, however, it is more limited than previously thought.
Antidepressants can have unpleasant side effects that patients want to avoid.
We must work hard to help people manage their pain and live well without relying on prescription pads.”
Professor Martin Underwood, of the University of Warwick, co-authored the paper
The review examined 26 systematic reviews from 2012 to 2022 involving more than 25,000 participants. It includes data on eight antidepressant classes and 22 pain conditions, including back pain, fibromyalgia, headache, postoperative pain, and irritable bowel syndrome. Serotonin-norepinephrine reuptake inhibitors (SNRI) antidepressants such as duloxetine have been found to be effective for the largest number of pain conditions, such as back pain, knee osteoarthritis, postoperative pain, fibromyalgia, and neuropathic pain (nerve pain).
In contrast, tricyclic antidepressants, such as amitriptyline, are the most commonly used antidepressants to treat pain in clinical practice, but reviews have shown that it is not clear how well they work, or whether they work in many pain conditions.
The use of antidepressants as a treatment for pain has recently gained worldwide attention. The 2021 guidelines for the management of chronic primary pain published by the National Institute for Health and Care Excellence (NICE) recommend against the use of pain medications other than antidepressants. The guidelines recommend different types of antidepressants for adults living with chronic primary pain, such as amitriptyline, citalopram, duloxetine, fluoxetine, paroxetine or sertraline.
Lead author Dr Giovanni Ferreira, from The Institute for Musculoskeletal Health at the University of Sydney and Sydney Musculoskeletal Health, said a more nuanced approach to prescribing antidepressants for pain was needed.
“Prescribing a list of antidepressants without carefully considering the evidence for each of those antidepressants for different pain conditions can mislead physicians and patients into thinking that all antidepressants have equal efficacy for pain conditions. We have shown that this is not the case.”
Co-author Dr Christina Abdel Shaheed, from The School of Public Health and Sydney Musculoskeletal Health at the University of Sydney, said:
“Findings from this review will help clinicians and patients weigh the benefits and harms of antidepressants for different pain conditions so they can make informed decisions about whether and when to use them.”
Dr Ferreira said there are many treatment options for pain, and people should not rely solely on pain medications to relieve pain.
“Some pain medications can play a role in pain management, but they need to be considered only as part of the solution. For some pain conditions, exercise, physiotherapy, and lifestyle changes can also help. Talk to your health professional to learn more about. For you What alternatives might be appropriate,”
This review distilled the evidence from more than 150 clinical trials into an accessible summary that clinicians can use to help them make better decisions for their chronic pain patients.
Current status of antidepressants worldwide
Most antidepressant prescriptions for pain are ‘off-label’, meaning these antidepressants are not approved to be prescribed for pain. Many antidepressants are thought to help reduce pain by acting on chemicals in the brain that can help reduce pain, such as serotonin. However, it is not known why some antidepressants improve pain.
The use of antidepressants has doubled in OECD countries from 2000 to 2015, and the use of ‘off-label’ prescriptions of antidepressants for pain is thought to be a contributing factor to this increase. Statistics from Canada, the United States, the United Kingdom, and Taiwan show that chronic pain is the most common condition in the elderly that leads to more antidepressant medications than depression.
Ferreira, GE, et al. (2023) Efficacy, safety, and tolerability of antidepressants for pain in adults: an overview of systematic reviews. BMJ. doi.org/10.1136/bmj-2022-072415.