A new study reveals what you should know before starting antidepressants for pain relief

Health experts have cautioned that a significant number of antidepressants prescribed for chronic pain may lack adequate evidence of their effectiveness.

A recent extensive investigation into medications used for long-term pain management has revealed that many of the commonly prescribed drugs have not been sufficiently researched for their adverse effects.

The Cochrane review, conducted by a team of scientists from UK universities, including Southampton and Newcastle, analyzed 176 trials involving nearly 30,000 patients who received antidepressants for chronic pain relief.

The drugs evaluated in the study were amitriptyline, fluoxetine, citalopram, paroxetine, sertraline, and duloxetine, with only the last one showing reliable evidence for pain alleviation.

The data from the World Health Organisation indicates that approximately one-third of people worldwide are living with chronic pain, and many are prescribed antidepressants to manage their symptoms.

“This is a global public health concern,” remarks lead author Professor Tamar Pincus.

“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.”

Amitriptyline is a widely used antidepressant for pain management, with around ten million prescriptions being issued in England over the past year at the recommended 10mg dose for pain relief. In comparison, five million prescriptions were written for higher doses recommended for depression.

While duloxetine saw approximately three and a half million prescriptions dispensed in England, the recommended doses remain the same for both depression and pain management.

This study, conducted over two years and endorsed by prominent healthcare organizations such as the UK’s National Institute for Health and Care Excellence (NICE) and the US Food and Drug Administration (FDA), represents the largest-ever evaluation of antidepressants.

According to the review, duloxetine consistently received the highest ratings among medications evaluated and demonstrated equivalent efficacy in treating fibromyalgia, musculoskeletal, and neuropathic pain conditions.

Additional findings indicate that:

• Duloxetine is equally effective in reducing pain at standard doses as it is at higher doses.
• Milnacipran was also successful in reducing pain, but due to a smaller number of studies involving fewer participants, there is less certainty compared to duloxetine.

“We simply cannot tell about other antidepressants,” adds Prof Tamar Pincus, “because sufficiently good studies are not available – but it does not mean that people should stop taking prescribed medication without consulting their GP.”

The researchers utilized a statistical approach that allowed them to merge data from pertinent studies and evaluate the impact of various drugs that had not been directly compared in individual trials.

“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,” points out University of Southampton researcher Dr. Hollie Birkinshaw.

“The only reliable evidence is for duloxetine. 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.”

Source: 10.1002/14651858

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