Antidepressants are commonly prescribed to treat pain, but new Australian research has revealed they offer little to no help for people suffering from chronic back pain and osteoarthritis – and may even be causing them harm

“The use of antidepressants to treat people with chronic back pain and osteoarthritis is increasing worldwide, but prior to our work, it was not clear whether antidepressants relieved pain or were safe,” said lead author Dr Giovanni Ferreira, postdoctoral research fellow at the Institute for Musculoskeletal Health at the University of Sydney.

“We conducted a review of all randomised clinical trials evaluating the efficacy of antidepressants for people with back pain or knee osteoarthritis and found that for back pain the antidepressants were either ineffective or provided a very small effect, which was unlikely to be perceived as worthwhile by most patients.”

“For people with osteoarthritis, effects were still small, but could be potentially perceived as worthwhile by some patients,” he told HealthTimes.

“This is concerning as some antidepressants significantly increase the risk of a person to experience adverse events. Many people are being treated with these medications that may not be helping their pain and may be doing them harm.”

The study was a systematic review and meta-analysis that included 33 randomised controlled trials with more than 5,000 participants with low back or neck pain, sciatica, or hip or knee osteoarthritis.

The trials tested six classes of antidepressants including serotonin-noradrenaline reuptake inhibitors (SNRIs) and tricyclic antidepressants.

Dr Ferreira said that each class of antidepressants carries a different of adverse events.

“Generally speaking, an important risk of using antidepressants is related to abruptly ceasing treatment with them.”

“It is very important not to abruptly cease treatment with antidepressant medicines.This can lead to withdrawal effects which can be distressing and sometimes present as serious health issues. These withdrawal effects include dizziness, nausea, anxiety, agitation, tremor, sweating, confusion, and sleep disturbance.”

Dr Ferreira said that the endorsement by clinical guidelines was a key driver behind the growing use of antidepressants to treat back pain and osteoarthritis. For sciatica, antidepressants are also recommended as first-line treatment for example – which made one finding from this review particularly surprising.

“Our analysis of studies in people with sciatica revealed that the findings were too uncertain, due to the poor quality of current trials, for any recommendations to be made for these patients”

“This was surprising, given that some guidelines recommend antidepressants as one of the main treatment options for people with back pain and leg symptoms.”

Dr Ferreira said the team were also surprised by their review of all the trials testing the efficacy of serotonin-norepinephrine reuptake inhibitors antidepressants for back pain. While they were sponsored by pharmaceutical companies, none of those trials demonstrated effects that would be considered worthwhile by most patients.

“We thought this was unexpected because trials funded and conducted by pharmaceutical companies tend to show more positive results than trials conducted by independent researchers with no ties to the industry. Even still the effects of these antidepressants were minimal.”

This study adds important information to an international body of evidence that underscores the very limited role of pharmacological treatments for back pain.

“The good news is that back pain and osteoarthritis can be successfully managed in many cases with non-pharmacological options that help with the pain just as much, or sometimes even more, than medications.”

“These include self-management programs and exercise for both conditions, and weight management programs for people with osteoarthritis for example”, Dr Ferreira said.

"More research is needed to resolve uncertainties about the efficacy of antidepressants for sciatica and osteoarthritis highlighted by this review”, he added.