Antidepressants for non-specific low-back pain

Low-back pain is a common condition affecting up to 80% of adults over their lifetime. In the vast majority of cases, low-back pain has no identifiable cause and is termed "non-specific".

Low-back pain is usually benign and self-limiting. It generally resolves in six weeks, with or without treatment.

However, up to 30% of individuals who report low-back pain go on to have recurrent or persistent symptoms. As a result, low-back pain is one of the most common reasons for medical visits and it results in huge economic losses across developed nations because of reduced productivity, work absence and early retirement.

Antidepressants are a common treatment for low-back pain. Physicians prescribe them to patients with back pain for three main reasons: to provide pain relief, help with sleep and reduce depression. However, the prescription of antidepressants as a treatment for back pain remains controversial because of conflicting scientific evidence.

This updated review evaluated whether antidepressants are beneficial in the management of non-specific low-back pain. We identified ten studies which compared antidepressants to a placebo (an inactive substance that has no treatment value). All patients in these studies had low-back pain as a primary complaint and some participants also had symptoms of depression.

We looked at the results of individual studies and also combined the results of several studies in larger analyses.

The review could find no convincing evidence that antidepressants relieve back pain or depression more effectively than placebo. Antidepressants did not result in any other apparent benefits in the treatment of back pain.

Antidepressants did cause side-effects, however, adequate information about these was not provided in the trials.

Patients with significant depression should not avoid antidepressants based on this review, as they continue to play an important role in the treatment of clinical depression. There is also evidence that antidepressants can help patients with other specific types of pain.

The review cautions that existing studies do not provide adequate evidence regarding antidepressants for low-back pain. There is a need for larger and more sophisticated studies to confirm the conclusions of this review. In the meantime, antidepressants should be regarded as an unproven treatment for non-specific low-back pain.

Authors' conclusions: 

There is no clear evidence that antidepressants are more effective than placebo in the management of patients with chronic low-back pain. These findings do not imply that severely depressed patients with back pain should not be treated with antidepressants; furthermore, there is evidence for their use in other forms of chronic pain.

Read the full abstract...
Background: 

Antidepressants are commonly used in the management of low-back pain. However, their use is controversial.

Objectives: 

The aim of this review was to determine whether antidepressants are more effective than placebo for the treatment of non-specific low-back pain.

Search strategy: 

Randomised controlled trials were identified from MEDLINE, EMBASE and PsycINFO (to November 2008), the Cochrane Central Register of Controlled Trials 2008, Issue 4, and previous systematic reviews.

Selection criteria: 

We included randomised controlled trials that compared antidepressant medication and placebo for patients with non-specific low-back pain and used at least one clinically relevant outcome measure.

Data collection and analysis: 

Two blinded review authors independently extracted data and assessed the risk of bias in the trials. Meta-analyses were used to examine the effect of antidepressants on pain, depression and function, and the effect of antidepressant type on pain. To account for studies that could not be pooled, additional qualitative analyses were performed using the levels of evidence recommended by the Cochrane Back Review Group.

Main results: 

Ten trials that compared antidepressants with placebo were included in this review. The pooled analyses showed no difference in pain relief (six trials (one trial with two treatment arms and a second trial with 3 treatment arms); standardized mean difference (SMD) -0.04 (95% confidence interval (CI) -0.25 to 0.17)) or depression (two trials; SMD 0.06 (95% CI -0.29 to 0.40)) between antidepressant and placebo treatments. The qualitative analyses found conflicting evidence on the effect of antidepressants on pain intensity in chronic low-back pain, and no clear evidence that antidepressants reduce depression in chronic low-back pain patients. Two pooled analyses showed no difference in pain relief between different types of antidepressants and placebo. Our findings were not altered by the sensitivity analyses, which varied the risk of bias allowed for inclusion in the meta-analyses to allow data from additional trials to be examined.

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