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Amitriptyline may effectively treat low back pain

Although treatment with low-dose amitriptyline did not achieve a significant difference in improvement of pain or work outcomes among patients with chronic low back pain at 6 months, it did reduce disability at 3 months without harmful adverse effects, according to a new study published in JAMA Internal Medicine.

“Antidepressants at low dose are commonly prescribed for the management of chronic low back pain and their use is recommended in international clinical guidelines. However, there is no evidence for their efficacy,” Donna M. Urquhart, PhD, from the School of Public Health and Preventive Medicine at Monash University, Melbourne, Australia, and colleagues wrote.

Urquhart and colleagues conducted a double-blind, randomized clinical trial to determine if antidepressants are effective in reducing pain, disability and work absence and hindrance among adults with chronic, nonspecific, low back pain.

The researchers randomly assigned 146 participants (mean age, 54.8 years; 61.6% men) to receive either low-dose amitriptyline (25 mg per day) or an active comparator (benztropine mesylate, 1 mg per day) for 6 months. About 80% of participants (n = 118) completed follow-up at 6 months.

Independent of baseline pain, patients treated with low-dose amitriptyline did not demonstrate greater pain reduction than the comparator at 6 (adjusted difference = –7.81; 95% CI, –15.7 to 0.1) or 3 months (adjusted difference = –1.05; 95% CI, –7.87 to 5.78).

At 6 months, disability did not statistically significantly differ between the groups (adjusted difference = –0.98; 95% CI, –2.42 to 0.46). Conversely, at 3 months, participants in the low-dose amitriptyline group had statistically significant improvements in disability (adjusted difference = –1.62; 95% CI, –2.88 to –0.36).

Work absence and hinderance did not differ between the groups at 3 months (adjusted difference for absence = 0.86; 95% CI, 0.32-2.31; hindrance = 0.78; 95% CI, 0.29-2.08) or 6 months (adjusted difference for absence = 1.51; 95% CI, 0.43-5.38; hindrance = 0.53; 95% CI, 0.19-1.51). The number of participants who withdrew because of adverse events was the same in each group (12%).

“The results of this trial suggest that the use of low-dose amitriptyline may be an effective treatment for chronic low back pain,” and colleagues concluded. “[The findings] provide support for large-scale clinical trials of low dose amitriptyline, with gradual dose escalation. In the meantime, it may be worth trying low-dose amitriptyline for these patients, especially if the only alternative is an opioid.” – by Alaina Tedesco

Disclosure: The authors report no relevant financial disclosures.