Minimal Benefit of Low-Dose Amitriptyline for Patients with Chronic Low Back Pain

Tricyclic antidepressants, particularly amitriptyline, frequently are prescribed to patients with chronic pain, but the evidence supporting this use is sparse. In this study, researchers randomized 146 adults (mean age, 55) with chronic low back pain (mean duration of pain, 14 years; mean pain intensity, 42 on a 100-point scale) to receive 6-month courses of daily amitriptyline (25 mg) or benztropine mesylate (Cogentin; 1 mg). All patients received usual care and nonopioid analgesics. Benztropine, an anticholinergic drug without known analgesic effects, was used to enhance blinding by mimicking amitriptyline's side effects.

At 3 months, the intervention group reported significantly less disability than did placebo patients, but this differen…