Prescribing antidepressants for chronic pain: careful consideration needed

By Rebecca Jenkins

There is a place for certain antidepressants in managing some pain conditions, but more consideration is needed in their prescription, an Australian-led review finds.

Off-label use of antidepressants to treat chronic pain was thought to be a factor in antidepressant use doubling in OECD countries from 2000 to 2015, the review authors said.

For their study, they conducted an extensive literature review and identified 26 systematic reviews that compared the efficacy of eight antidepressant classes against placebo for 22 pain conditions, giving 42 distinct comparisons.

None of the reviews gave a high certainty of evidence on the efficacy of antidepressants for pain, the researchers wrote in The BMJ.

Evidence of efficacy was found in eleven of the 42 comparisons, but for the remaining 31 comparisons, antidepressants were either inefficacious or the evidence was inconclusive.

‘Some antidepressants were efficacious for some pain conditions; however, efficacy appears to depend on the  condition and class of antidepressant,’ the authors wrote.

‘The findings suggest that a more nuanced approach is needed when prescribing antidepressants for pain conditions.’

There was moderate certainty evidence that serotonin-norepinephrine reuptake inhibitors (SNRIs) were effective for back pain, postoperative pain, neuropathic pain and fibromyalgia.

Low-certainty evidence suggested SNRIs were efficacious for aromatase inhibitor therapy-induced pain in breast cancer and for depression and comorbid chronic pain. There was also low-certainty evidence supporting selective serotonin reuptake inhibitors for depression and comorbid chronic pain and tricyclic antidepressants for irritable bowel syndrome, neuropathic pain and chronic tension-type headache.

Lead author, Dr Giovanni Ferreira, PhD, a Fellow of The University of Sydney’s Sydney Musculoskeletal Health, said the role of antidepressants in helping people living with certain chronic pain conditions was much more limited than previously believed.

‘There needs to be a careful consideration of the type of antidepressants and the chronic pain condition for which it is being prescribed,’ he told Medicine Today.

The authors acknowledged that one limitation of the study was that 45% of included trials had ties to the industry, with 68% of the identified SNRI trials having industry links.

‘High-quality trials that are conducted by independent investigators, free from industry influence, can help fill important gaps in the literature around antidepressants for pain,’ Dr Ferreira said.

Coauthor Professor Ric Day, Professor of Clinical Pharmacology at UNSW Medicine’s St Vincent’s Clinical School, Sydney, said prescribers should first optimise patient education, weight loss, appropriate exercise and then simple analgesics, such as paracetamol and low-dose NSAID, before considering an antidepressant for pain management.

‘If there are contributing factors of depression or sleep deprivation, then adjuvant analgesia via antidepressants might be helpful to some. Start with very low doses and monitor for effect and adverse effects,’ he told Medicine Today.

BMJ 2023; 380: e072415.