People over 65 are being prescribed antidepressants to treat pain despite poor evidence that the drugs work, potentially exposing them to harm, according to a new study that calls for a review of prescribing guidelines.
Researchers led by Dr Sujita Narayan from the University of Sydney’s Musculoskeletal Institute Health reviewed the findings of 15 trials with 1,369 participants to determine how antidepressants affect pain relief and adverse events in older adults.
Based on these studies, Narayan told Guardian Australia there are many international guidelines recommending the use of antidepressants for pain, “especially for chronic pain”.
“Antidepressants are now used more for pain than for depression in older people. We wanted to understand what evidence there is in terms of the benefits and impact of antidepressant use for pain relief in this population.”
But the researchers found a lack of evidence to support the use of antidepressants for the treatment of most pain conditions in older adults.
Most of the trials they examined had small sample sizes of less than 100 participants, making it difficult to generalize any findings about the drugs that improve pain, and researchers involved in many of the trials had conflicting had interests including links to pharmaceutical companies producing pain relief drugs. , potentially biasing the results.
The research, published in the British Journal of Clinical Pharmacology on Friday, found limited evidence to support the use of antidepressants such as duloxetine for managing pain associated with knee osteoarthritis, but even then the effect was small and there was an increased risk of side effects.
The study authors acknowledged that pain can lead to depression and that antidepressants may be used by some doctors to address both conditions, but said that the benefit when used primarily for pain relief was small and inconsistent.
The benefits of prescribing must be weighed against the risk of side effects, with the study finding that older people taking antidepressants experienced negative side effects such as falling, feeling dizzy and being injured.
Narayan said many of the studies looking at the use of antidepressants to treat pain also involved younger participants, but people over 65 may have health conditions that make using antidepressants more risky.
There can also be harmful side effects when trying to stop antidepressant medication, the study said, and there were growing concern about the problems that people experience when they come off the medication.
“There needs to be a review of the existing guidelines, especially for older people, because there is very little evidence to support the use of antidepressants for pain,” Narayan said. “The evidence is that it causes more harm than good in most of this population.”
She encouraged people to talk to their doctor before discontinuing any medication, and warned that antidepressant medications should be discontinued extremely careful under medicine supervision to reduce risks of side effects.
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A senior specialist in geriatric medicine, Prof Joseph Ibrahim, said it can be complex to assess and treat pain conditions in older people because chronic pain can lead to feelings of depression and anxiety.
Doctors had to weigh the cause of those conditions, along with the impact of other conditions the person may have, and evaluate possible drug interactions, risks and side effects, he said.
Ibrahim said that older people often feel that their pain and associated feelings of despair are dismissed or ignored, and that this can lead to undertreatment.
“It’s a real juggling act,” he said.
A clinical research fellow at the National Health Service in London who has researched the prescribing and side effects of antidepressants, Dr Mark Horowitz, described Narayan’s paper as “very useful”. He said antidepressants have shown no long-term efficacy for treating chronic pain in adults of any age.
He said the drugs were generally over-prescribed. “High and increasing rates of antidepressant prescribing among older adults is becoming a major concern in Australia,” he said.
“Sixty percent of older adults in aged care facilities are now prescribed antidepressants. We know in this age group that these drugs are associated with an increased risk of falling, fractures, strokes and an early deathas well as bleeding risks, osteoporosis, cataracts and some with a increased risk of dementia.”
