The efficacy of amitriptyline and acetaminophen in the management of acute low back pain

Thirty-nine patients with acute low back pain were treated with amitriptyline (150 mg/d) or acetaminophen (2,000 mg/d) in a controlled double-blind design for 5 weeks. Both groups revealed mild depression, normal coping, and increased anxiety at the beginning, with significant improvement in anxiety state and pain at the end of treatment. A repeated measures analysis of variance demonstrated that amitriptyline was more effective than acetaminophen in reducing pain intensity from the second week of treatment. Age and depression were the only significant pretreatment predictors of posttreatment pain. The study evaluates the significance of these findings.