MELBOURNE, Australia—So far, there is little evidence that antidepressants relieve either pain or depression in patients with nonspecific chronic low back pain (LBP), according to a new review of 10 studies in the Cochrane Database of Systematic Reviews.¹

"We found no clear evidence to support the clinicians' prescription of antidepressants in reducing pain and depression for patients with chronic LBP," write researchers led by Donna Urquhart, PhD, research fellow at Monash University in Melbourne, Australia. The researchers note that severely depressed patients with back pain may still benefit from antidepressants.

Placebo-controlled trials in various types of LBP

The meta-analysis compared antidepressants with placebo among chronic LBP patients with diagnoses including radicular symptoms, herniated discs, or spondylolisthesis. Two studies revealed that patients taking antidepressants reported less pain than their placebo counterparts. There is evidence that tricyclic antidepressants can promote restorative sleep and relax painful muscles in other forms of chronic pain including fibromyalgia and neuropathic pain, the study authors note. In addition, seven studies found that there was no difference in depression among patients receiving antidepressants who also had LBP compared with their counterparts receiving placebo.

In most of the studies patients were permitted to take their regular medication including aspirin and nonsteroidal anti-inflammatory drugs. The study included several types of antidepressants including selective serotonin reuptake inhibitors, tricyclic antidepressants, and atypical antidepressants such as aminoketone antidepressants. One study included patients who had significant depression; four studies included patients who either were depressed or not depressed; three studies excluded depressed patients; and in two studies, depression diagnosis was unclear.
    
More study needed

"More studies with large homogenous study populations such as LBP with radiculupathy that need high methodologic standards and involve long-term follow up are required," the authors conclude. "Future research should focus on the (cost) effectiveness of antidepressants for the management of patients with chronic LBP."

To that end, two additional trials identified in September 2007 are awaiting assessment.

Don't throw the baby out with the bathwater

My concerns about [the Urquhart et al] review is that they excluded Atkinson's large 1998 study for reasons that I can't convince myself were justified," said Thomas O. Staiger, MD, associate professor of medicine at the University of Washington in Seattle. The review authors cited absence of follow-up means and standard deviations (which appeared in the June 1998 issue of Pain) as reasons for exclusion from their study. Dr. Staiger told MSKreport.com that the information was in fact available in their study's tables. "If Atkinson's findings are taken into account, which I think they should be, at this point I think the evidence still supports that tricyclics are moderately effective for decreasing pain in patients with chronic low back pain and warrant a trial in patients who don't have contraindications."
 
Dr. Staiger and colleagues published a review in 2003 that found tricyclic and tetracyclic antidepressants may be mildly to moderately effective in reducing chronic LBP. 

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