Efficacy and Safety of Extended-Release Clonidine Hydrochloride for Attention Deficit Hyperactivity Disorder in Chinese Children and Adolescents: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial

INTRODUCTION: Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental condition in children and adolescents, yet randomized controlled trial evidence supporting pharmacological treatment in Chinese populations remains limited. This study evaluated the efficacy and safety of clonidine hydrochloride extended-release tablets (CLON-XR) as monotherapies for ADHD among Chinese children and adolescents. MATERIALS AND METHODS: In this 6-week, multicenter, randomized, double-blind, placebo-controlled phase 3 trial, 75 patients aged 6-17 years with ADHD were assigned (2:1) to receive once-daily CLON-XR (target dosage 0.2 mg/day) or placebo. The primary endpoint was the change from baseline to week 5 in the Swanson, Nolan, and Pelham Version-IV (SNAP-IV) total score. Secondary endpoints included SNAP-IV subscales, Clinical Global Impression-Severity (CGI-S) and Improvement (CGI-I) scores, and safety assessments. RESULTS: < 0.05). The incidence of treatment-emergent adverse events (TEAEs) in the CLON-XR group was comparable with that in the placebo group; the TEAEs were mild, and the dropout rate was low (5.3%). No serious adverse events or clinically significant vital sign abnormalities were reported. CONCLUSIONS: CLON-XR was efficacious and well tolerated in Chinese children and adolescents with ADHD, supporting its potential as a nonstimulant treatment option in this population. These findings provide evidence for ADHD management in China and suggest that further investigations in longer-term and real-world settings are needed.