Review suggests antidepressants of limited efficacy in chronic pain

8th February 2023

Antidepressant efficacy in the management of chronic pain conditions appears to be limited according to an overview of systematic reviews

An overview of systematic reviews by researchers from Australia and the UK which examined the use of an antidepressant for the management of a range of chronic pain conditions, has concluded that the evidence of efficacy for all classes of drugs was moderate to low.

The presence of chronic pain is a common condition with one US survey finding that 50.2 million adults reported experiencing pain on most days or every day. Although both opioids and non-steroidal anti-inflammatory agents can be used to treat chronic pain, guidance from NICE in the UK, advises that the pharmacological management of such pain should involve the use of an antidepressant and which should be either amitriptyline, citalopram, duloxetine, fluoxetine, paroxetine or sertraline. But exactly how effective are antidepressant drugs for the management of chronic pain was the subject of the recent review by the Australian and UK researchers. The team undertook an overview of all available systematic reviews describing the use of an antidepressant (compared to placebo) for the management of any chronic painful condition in adults. The researchers set their primary outcome as pain and which could be measured with any instrument. The pain outcomes were then converted to a 0 to 100 scale and for which 0 represented no pain and 100, worst pain.

Antidepressant use and pain outcomes

A total of 26 studies with over 25,000 participants were included in the final analysis and which covered 22 distinct pain conditions and 42 antidepressants (8 different classes) versus placebo comparisons.

Overall, none of the reviews provided high certainty evidence on the efficacy of an antidepressant for pain in the management of any of the conditions examined. There were 11 comparisons of 9 different conditions where antidepressants were effective, largely serotonin-norepinephrine (noradrenaline) re-uptake inhibitors. This latter class was effective (mainly duloxetine) for back pain, postoperative pain, neuropathic pain and fibromyalgia. In the other cases, the antidepressants were deemed to be either ineffective or the evidence was inconclusive.

Interestingly, the researchers found that 74% of tricyclic antidepressant prescriptions were for a pain condition yet of 14 pain problems examined, this class of drugs were only effective for three conditions (irritable bowel syndrome, neuropathic pain and chronic tension-type headache). However, the certainty of the evidence was low in each case.

The authors concluded that overall, the efficacy of antidepressants was found in only 11 of the 42 comparisons and suggested that a more nuanced approach was needed when using these drugs for a painful condition.

Citation
Ferreira GE et al. Efficacy, safety, and tolerability of antidepressants for pain in adults: overview of systematic reviews. BMJ 2023