Millions of antidepressants are dispensed each year for chronic pain despite little evidence that they work, a major scientific study has found.
A study on medications to manage long-term pain found that the harms of many of the commonly recommended medications have been poorly researched.
Still, in the past 12 months, about 10 million prescriptions for drugs including amitriptyline and fluoxetine, better known as Prozac, were handed out for long-term pain management.
Scientists said there was a “shocking” lack of evidence about the long-term effects of taking antidepressants, putting hundreds of thousands of people at significant risk of harm.
Scientists have told doctors to focus on more “holistic” therapies, including lifestyle changes
They urged doctors to prioritize drugs where there is some evidence of effectiveness and focus on more “holistic” therapies, such as lifestyle changes.
With about one in three people suffering from chronic pain, antidepressant use is on the rise as doctors try to relieve symptoms without using potentially addictive opioids.
Other drugs such as paracetamol and ibuprofen are now considered both ineffective and potentially harmful, leaving GPs with limited options.
The two-year Cochrane study was the largest-ever review of antidepressants recommended by leading bodies, including the UK’s National Institute for Health and Care Excellence (NICE).
The “gold standard” review looked at 176 studies involving nearly 30,000 people and 89 treatment types, ranging from different types of antidepressants to psychological therapies and physical therapy.
Despite usually being prescribed for six months, the Cochrane review found the average trial length was only 10 weeks.
It found there was “insufficient evidence” to determine how effective or harmful most antidepressants are, with scientists particularly concerned about the lack of research on long-term use.
Duloxetine consistently scored highest for pain relief and was found to be equally effective for fibromyalgia, musculoskeletal and neuropathic pain conditions, which are eligible for the drugs according to NICE guidelines.
Milnacipran was also effective at reducing pain, but scientists had less confidence in the research because there were fewer studies involving significantly fewer people.
Medications such as paracetamol and ibuprofen are now considered both ineffective and potentially harmful, leaving GPs with limited options
Dr. Gavin Stewart, from the University of Newcastle and co-author of the review, said it was ‘shocking’ that current evidence was being used as a basis for prescribing and called on the watchdog to update the guidelines to reflect the new scientific evidence display.
He said: ‘This evidence base for chronic pain is quite shocking when you think about the social cost of this – it’s off scale.
‘That we pay so little attention to it is nothing short of shocking.
“We are calling on governing health agencies NICE and the FDA to update their guidelines to reflect the new scientific evidence, and funders to stop supporting small and flawed studies.”
Amitriptyline is one of the three most commonly prescribed antidepressants for pain management worldwide, and researchers suggest it is the ‘go-to’ drug for general practitioners because it is cheap, costing about 69 pence per dose.
In the past 12 months, about ten million prescriptions have been given to patients in England at the recommended dose of 10mg for pain.
By comparison, five million prescriptions were given at the higher doses recommended for depression.
Some 3.5 million prescriptions for duloxetine have been dispensed in England, but there is only one dose for all conditions, despite lower doses appearing to be equally effective.
Lead author Professor Tamar Pincus from the University of Southampton said the use of antidepressants is a ‘global public health problem’.
She said: ‘Chronic pain is a problem for millions of people who are prescribed antidepressants without sufficient scientific evidence that they help, nor an understanding of their long-term health effects.
“Our study 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 in time.
“While we found that duloxetine provided short-term pain relief in patients we studied, we remain concerned about the potential long-term harm due to the gaps in the current evidence.”
With 30 years of pain research, she suggested there is growing evidence that “living better in a truly holistic way — more physical activity, stress reduction, lifestyle changes” offers the greatest benefits.
She added, “While it may seem like you have to invest a lot for that to happen, it really pays off in dividends in terms of a reduction in health care seeking after the fact. And it touches so many chronic conditions, not just pain, if you can create these changes.”
Drug watchdog NICE said there were no plans to change guidelines based on the review, noting that the guidelines state that GPs should only ‘consider’ offering antidepressants.
It said the 2021 guidelines recommend that antidepressants, including duloxetine, be considered for people aged 18 and over to treat chronic primary pain “after a full discussion of the benefits and harms.”
They said the evidence shows these drugs can help with quality of life, pain, sleep and mental health problems, even in the absence of a diagnosis of depression.
The spokesperson said: ‘The committee felt that these may be beneficial for some patients and that clinicians should be able to choose from the range of therapies based on individual need, background and acceptance of side effects.
NICE has conducted a careful and comprehensive review of the recent findings of the Cochrane publication and we have concluded that there is not enough new evidence as of 2021 to warrant an update at this stage of the recommendations on the use of antidepressants in our guideline for justify chronic pain.”