Clonidine, an α(2)-adrenergic agonist, is approved in the US as an extended-release (XR)
tablet for the treatment of
attention-deficit hyperactivity disorder (
ADHD) in children and adolescents (aged 6-17 years). In two, randomized, double-blind, multicenter, phase III trials of 8 weeks' duration,
clonidine XR improved the symptoms of
ADHD in children and adolescents. Significantly greater reductions from baseline in
ADHD rating scale IV (
ADHD-RS-IV) total scores at week 5 (primary endpoint) were achieved by recipients of
clonidine XR 0.2 and 0.4 mg/day monotherapy than by recipients of placebo. When added to patients' normal stimulant regimen, significantly greater reductions from baseline in
ADHD-RS-IV total scores at week 5 (primary endpoint) were achieved with a flexible dose of
clonidine XR 0.1-0.4 mg/day than with placebo. Symptomatic improvement of
ADHD was achieved following 2 weeks' treatment with
clonidine XR. In both trials, significantly greater reductions from baseline in
ADHD-RS-IV total scores were apparent at week 2 onwards for recipients of
clonidine XR than for recipients of placebo.
Clonidine XR was generally well tolerated as monotherapy and as adjunctive
therapy with stimulant regimens in clinical trials in children and adolescents.