Do antidepressant medications relieve chronic low back pain?

BACKGROUND: Antidepressant medications are commonly prescribed for patients with chronic low back pain. A literature synthesis was performed to determine whether antidepressants are more effective than placebos in decreasing pain, disability, depression, and analgesic medication use in such patients.
METHODS: English-language journal articles were identified from MEDLINE and PsycLIT databases, bibliographies, and inquiries to researchers and drug companies. Articles were included if they reported data from placebo-controlled or drug comparison trials of antidepressants for patients with low back pain. Six articles met these criteria.
RESULTS: Three studies compared the effects of antidepressants and placebos on pain; two found no difference and one found a trend toward superiority of imipramine for patient-rated symptoms but no difference in investigator ratings. Effects on functional disability were examined in three antidepressant-placebo comparisons; only one found the antidepressant to be more effective. Antidepressant effects of an antidepressant vs placebo were compared in three studies; none found a significant difference. Effects on analgesic medication use were compared in three studies; one found amitriptyline to be superior and the others found no difference. Serious methodologic flaws characterized all six studies, and insufficient reporting of data precluded meta-analysis.
CONCLUSIONS: The literature has not demonstrated that antidepressants are superior to placebos in improving low back pain or related problems. However, further randomized controlled trials are needed to determine whether antidepressants are useful for low back pain.