Systematic review of antidepressants in the treatment of chronic low back pain

Background. Three previous reviews have reached conflicting conclusions regarding the efficacy of antidepressants for patients with back pain. Objectives. To systematically review the efficacy of antidepressants for the treatment of patients with back pain and to determine whether there is evidence that outcomes vary between classes of antidepressants. Materials and Methods. Best evidence synthesis of randomized, placebo- controlled trials of oral antidepressive agents in patients with back pain. Studies were identified by searching MEDLINE, PsycINFO, and the Cochrane Controlled Trials Registry. Two independent reviewers performed data extraction and assessed included studies with a 22- point methodologic quality assessment scale. Effect sizes were calculated if sufficient data were available. Results. Twenty- two trials of antidepressants for the treatment of back pain were identified, of which seven studies of chronic low back pain met inclusion criteria. Among studies using antidepressants that inhibit norepinephrine reuptake ( tricyclic or tetracyclic antidepressants), four of five found significant improvement in at least one relevant outcome measure. Assessment of these agents' impact on functional measures produced mixed results. No benefit in pain relief or functional status was found in three studies of antidepressants that do not inhibit norepinephrine reuptake. Conclusions. Based on a small number of studies, tricyclic and tetracyclic antidepressants appear to produce moderate symptom reductions for patients with chronic low back pain. This benefit appears to be independent of depression status. SSRIs do not appear to be beneficial for patients with chronic low back pain. There is conflicting evidence whether antidepressants improve functional status of patients with chronic low back pain.