Low back pain affects millions of Australians each year and is responsible for the most years lived with disability worldwide.  

The most commonly used treatments for low back pain are medicines that aim to reduce this pain.

Often, antidepressants are prescribed to people with low back pain when other medicines such as ibuprofen or paracetamol fail to provide relief.

The new study, published in Systematic Reviews recently, consolidated the results of 17 studies involving more than 2500 adult participants.

The researchers compared the results of five different antidepressant medicine classes to the use of placebos.

Lead author Michael Ferraro, doctoral candidate at UNSW Medicine & Health and Neuroscience Research Australia (NeuRA), said: “Antidepressants are commonly prescribed to treat the symptoms of low back pain.

“However, prescription rates for antidepressants to manage low back pain are increasing worldwide, despite unclear evidence to support their efficacy and safety and conflicting advice in clinical guidelines.”

The research team investigated the differences in outcomes for pain, safety, function and depressive symptoms between people taking antidepressants and placebos.

Mr Ferraro said: “We found that treating low back pain with antidepressants failed to lead to reductions in what patients might consider important benefits for pain or function.

“We also discovered that people taking antidepressants for low back pain are more likely to stop treatment and experience side effects and might even experience more serious side effects.

“If people are taking antidepressants for low back pain and have any concerns about their treatment, they should consult their medical physician for advice.”

Findings challenge clinical guidelines

The results of the study challenge six international guidelines that recommend the use of antidepressant medicines for chronic low back pain.  

In particular, the United States’ clinical guideline endorses duloxetine, a serotonin and norepinephrine reuptake inhibitor, for the treatment of chronic low back pain.

Mr Ferraro and colleagues, however, found no important pain-relieving effects from the use of duloxetine or, any other class or dose of antidepressant medicines.

“We believe the US recommendation for duloxetine could be reconsidered in light of our findings,” he said.

“Ongoing recommendations for the use of antidepressants to treat low back pain are concerning, particularly given the increased risk of side effects.”

Further research needed

Although the researchers found no important benefits for low back pain treatment with antidepressants, they acknowledged the low quality of studies examined in their systematic review limited the certainty of their findings.

Mr Ferraro said: “It is difficult to estimate the true effects of such medicines being used to treat low back pain.

“The majority of the studies were considered to be at high risk of bias and interestingly, the studies which showed the most promise were industry-sponsored.

“We recommend future research focuses on other types of medicines that may provide benefit to adults with low back pain, as well as non-pharmacological treatments, such as physiotherapy and exercise.”

Find the study, “Efficacy, acceptability, and safety of antidepressants for low back pain: a systematic review and meta-analysis”, in Systematic Reviews.