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

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

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.

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.

(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.