Low dose amitriptyline in ankylosing spondylitis: a short term, double blind, placebo controlled study

Abstract

Objective: To define the effect of low dose amitriptyline on fatigue, pain, and stiffness in patients with ankylosing spondylitis (AS).

Methods: One hundred consecutive patients with AS were randomized to receive low dose amitriptyline up to 30 mg nightly or placebo for 2 weeks. Patients were assessed by the Bath Ankylosing Spondylitis Disease Activity (BASDAI) and Functional (BASFI) Indices pre and post-treatment.

Results: Eighty-eight patients (44 amitriptyline, 44 placebo) completed the study. Eight (5 amitriptyline, 3 placebo) stopped treatment because of side effects (e.g., drowsiness, dryness of mouth) and 4 provided insufficient data. Compared to placebo, the patients taking amitriptyline showed significantly greater improvement in restful sleep (66 vs 20%; p < 0.001) and their disease activity scores [BASDAI amitriptyline 1.18 (23%) vs placebo 0.52 (10%); p = 0.024]. All other variables showed a trend to greater improvement by amitriptyline, although the differences were not statistically significant.

Conclusion: (1) In a 2 week study, low dose amitriptyline significantly improved sleep in AS and was well tolerated; (2) as defined by BASDAI, there was a significant reduction in disease activity with amitriptyline; (3) compared to placebo, there was a nonsignificant trend toward improvement in function; and (4) in spite of improvement in pain, fatigue, and sleep with amitriptyline, stiffness was not increased.