There is insufficient evidence to justify the use of most antidepressants that are currently prescribed for chronic pain, Cochrane reviewers have concluded.
A team from Newcastle and Southampton universities analysed 175 trials of almost 30,000 patients and found only duloxetine was associated with reliable evidence of pain relief at least in the short-term for fibromyalgia, musculoskeletal, and neuropathic pain conditions.
There was no evidence of benefit for amitriptyline which the researchers said was the most commonly prescribed antidepressant for pain management worldwide.
Other drugs for which there was a lack of evidence in chronic pain were fluoxetine, citalopram, paroxetine, and sertraline, the review found.
And data on long-term safety of antidepressants in this context was particularly poor, the researchers noted, saying they were ‘uncertain’ about unwanted effects and this needs to be studied further.
But the team stressed that ‘adopting a person-centred approach is critical’ concluding: ‘Pain is a very individual experience and certain medications may work for people even while the research evidence is inconclusive or unavailable.
‘Future studies should last longer and focus on unwanted effects of antidepressants.’
A guideline last year from NICE on medicines associated with withdrawal or dependence recommended regular reviews for patients on antidepressants and drugs for chronic pain.
Co-author Dr Gavin Stewart a statistician at Newcastle University, said: ‘Our study is one of the biggest of its kind and demonstrates the need for large-scale studies in this field.
‘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.’
Study lead Professor Tamar Pincus, who researches the psychological aspects of chronic pain at the University of Southampton, said: ‘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.’
But she stressed the findings did not mean people should stop taking prescribed medication without consulting their GP.
Dr Cathy Stannard, clinical lead on the NICE Guideline for Chronic Pain said: ‘This well conducted review adds to the substantial evidence we now have that shows that the use of medicines to treat long term pain is disappointing.’
She added that the conclusion that the best evidence is for duloxetine is unsurprising because trials for this newer drug were more rigorously done.
‘The study rightly highlights the significant adverse effect that chronic pain has on the quality of life for the people living with it. It’s equally important to emphasise the many social and psychological influences on the pain experience.
‘There is good evidence that for people with pain, compassionate and consistent relationships with clinicians remain the foundations of successful care.’