Scientists Warn ‘No Reliable Evidence’ Antidepressants Can Treat Chronic Pain
Scientists have warned many antidepressants used for chronic pain are being prescribed without adequate evidence of their effectiveness.
A major investigation into medications has found that despite hundreds of thousands of people being given recommended drugs to manage long-term pain, there is “no reliable evidence” for their long-term safety or reliability.
The two-year study was one of the largest-ever studies of antidepressants.
These medications are commonly recommended by bodies such as UK’s National Institute for Health and Care Excellence (NICE) and the Food and Drug Administration (FDA) in the USA.
The Cochrane review, led by scientists from several UK universities including Newcastle University and the University of Southampton, examined 176 trials consisting of nearly 30,000 patients involved in assessments that prescribed antidepressants for chronic pain.
NICE chronic pain guidance from two years ago supported the use of antidepressants, but it said that there is still “insufficient” evidence since 2021 to warrant an update.
Study ‘One of the Biggest of Its Kind’
Among the drugs studied were amitriptyline, fluoxetine, citalopram, paroxetine, sertraline, and duloxetine. Only duloxetine showed reliable evidence for pain relief.
NHS guidelines say that antidepressants such as amitriptyline can be used for some chronic-pain conditions such as neuropathic pain.
Statistician Gavin Stewart, review co-author from Newcastle University, said: “Our study is one of the biggest of its kind and demonstrates the need for large-scale studies in this field. We would encourage funders to support high-quality studies into the use of antidepressants for chronic pain.
“Data is often complex and nuanced but the evidence underpinning the use of these treatments is not conclusive for most of the antidepressants we studied and, therefore, current treatment options are hard to justify.”
Stewart called on NICE and the FDA to update their guidelines “and on funders to stop supporting small and flawed trials.”
Lead author Professor Tamar Pincus, from the University of Southampton, said: “This is a global public health concern. Chronic pain is a problem for millions who are prescribed antidepressants without sufficient scientific proof they help, nor an understanding of the long-term impact on health.
“Our review found no reliable evidence for the long-term efficacy of any antidepressant, and no reliable evidence for their safety for chronic pain at any point.
“Though we did find that duloxetine provided short-term pain relief for patients we studied, we remain concerned about its possible long-term harm due to the gaps in current evidence.”
“We simply cannot tell about other antidepressants because sufficiently good studies are not available—but it does not mean that people should stop taking prescribed medication without consulting their GP,” she added.
She said that in 2020 to 2021, there were around 15 million prescriptions in England at low doses for amitriptyline.
Person-Centred Approach
Hollie Birkinshaw, a University of Southampton researcher, said: “Though previous investigations show that some antidepressants might relieve pain, there has never been a comprehensive study examining all medications across all chronic conditions—until now.
“The only reliable evidence is for duloxetine,” she said.
“Adopting a person-centred approach is critical to treatment and, when patients and clinicians decide together to try antidepressants, they should start from the drug for which there is good evidence,” she added.
A NICE spokesman said: “Our guideline on chronic pain published in 2021 recommends antidepressants, including duloxetine, can be considered for people aged 18 years and over to manage chronic primary pain, after a full discussion of the benefits and harms. This is because the evidence shows these medicines may help with quality of life, pain, sleep, and psychological distress, even in the absence of a diagnosis of depression.
“The committee considered that these could be beneficial to some patients and clinicians should be able to choose from the range of therapies based on the individual’s needs, background, and acceptance of adverse events.
“NICE has conducted a careful and comprehensive review of the recent Cochrane publication findings and we have concluded that there is insufficient new evidence since 2021 to warrant an update to the recommendations on antidepressant use in our chronic pain guideline at this stage.”
PA Media contributed to this report.
