Safety and efficacy of clonidine hydrochloride extended –release (CLON-XR) for treatment of attention deficit hyperactivity disorder in Chinese children and adolescents: a multi-center, placebo-controlled, randomized, double-blind study

Abstract Background While clonidine hydrochloride extended-release tablets (CLON-XR) have been approved by FDA for the treatment of ADHD, clinical data regarding its safety and efficacy in Chinese children and adolescents is limited. This present study is the first placebo-controlled, randomized, double-blind clinical trial of CLON-XR in the treatment of ADHD children and adolescents in China. Methods A total of 75 children with ADHD aged 6 to 17 were randomly assigned to the experimental group and placebo group in the ratio of 2:1, and received treatment for 6 weeks. Data from the Swanson Nolan and Pelham Version-IV (SNAP-IV) and the Clinical Global Impression (CGI) were evaluated. Safety measures included treatment-emergent adverse events (TEAEs), vital signs, laboratory assessments and electrocardiograms. Results ADHD symptoms had been significantly improved after treatment of CLON-XR since the first week. At week 5, the decrease in SNAP-IV total scores in CLON-XR group (17.5 ± 11.86) was statistically significantly more than that in the placebo group (10.3 ± 11.43; p < 0.05), and the degree of improvement in the SNAP-IV hyperactivity/ impulsivity and inattention subscale and the CGI scale in the experimental group from baseline to week 5 was also statistically significantly higher than that in the placebo group ( p < 0.05). CLON-XR was effective in the treatment of ADHD, regardless of age and gender. The incidence of TEAEs in CLON-XR group was comparable to that in placebo group, and the TEAEs were mild and the dropout rate was low (5.3%). Conclusions The nonstimulant medication CLON-XR can significantly improve the core symptoms (attention deficit and hyperactivity/impulsivity) and overall function in ADHD patients with no addiction, mild adverse reactions, and good compliance and tolerability. It has the potential to improve sleep efficiency and can be considered a recommended drug for the treatment of ADHD children and adolescents in China.