Abstract
Objective:
To evaluate the tolerability, safety, and preliminary efficacy of extended-release guanfacine in children with chronic tic disorders, including Tourette's disorder (collectively referred to as CTD).
Methods:
This was a multisite, 8-week, randomized, double-blind, placebo-controlled trial. The primary outcome measure was the Yale Global Tic Severity Scale (YGTSS) total score. Key secondary outcomes included the Improvement item of Clinical Global Impressions-Improvement (CGI-I) scale and the Tic Symptom Self-report (TSSR). Adverse events were monitored at each visit.
Results:
Thirty-four subjects (23 boys and 11 girls) of ages 6 to 17 years (mean = 11.1 ± 3.1) with CTD were randomly assigned to extended-release guanfacine (
n
= 16) or placebo (
n
= 18). At baseline, the mean YGTSS total score was 26.3 ± 6.6 for the guanfacine group versus 27.7 ± 8.7 for the placebo group. Within the guanfacine group (mean final daily dose of 2.6 ± 1.1 mg,
n
= 14), the mean YGTSS total score declined to 23.6 ± 6.42 [
t
(15) = 1.84,
p
= 0.08; effect size = 0.35]. The results were similar in the placebo group with a score of 24.7 ± 10.54 at week 8 [
t
(17) = 1.83,
p
= 0.08; effect size = 0.38]. There was no significant difference in the rate of positive response on the CGI-I between the guanfacine group and placebo (19% [3/16] vs. 22% [4/18],
p
= 1.0). The most common adverse events were fatigue, drowsiness, dry mouth, headache, and irritability. Two subjects in the guanfacine group discontinued early—one because of an adverse event (depressed mood) and one because of lack of efficacy; two subjects in the placebo group discontinued because of lack of efficacy.
Conclusions:
This pilot study did not confirm a clinically meaningful effect size within the guanfacine group. These results do not support the launch of a larger efficacy trial for tics in children and adolescents with CTD.
