Efficacy and duration of effect of extended-release dexmethylphenidate versus placebo in schoolchildren with attention-deficit/hyperactivity disorder

Objective: The aim of this study was to assess changes in symptomatology of attention-deficit/hyperactivity disorder (ADHD) with extended-release dexmethylphenidate (d-MPH-ER) versus placebo in a laboratory classroom setting. Methods: This double-blind, placebo-controlled, crossover study randomized 54 children 6-12 years of age, stabilized on methylphenidate 20-40 mg/day. Patients participated in a practice day, then received 5 days of treatment with d-MPH-ER 20 mg/day or placebo. After a 1-day wash-out, they returned to the classroom and received 1 dose of their assigned treatment. Evaluations occurred predose and at postdose hours 1, 2, 4, 6, 8, 9, 10, 11, and 12. Children were then crossed over to the alternate treatment, using identical protocol. Primary efficacy variable was the Swanson, Kotkin, Agler, M-Flynn, and Pelham rating scale (SKAMP)-Combined scores, and primary analysis time point was 1 hour postdose; secondary efficacy variables over 12 hours included SKAMP-Attention and -Deportment scores and written math test results. Safety was assessed by adverse event (AE) recording following each period. Vital signs were recorded at each visit; laboratory tests were conducted at screening and final visit. Results: D-MPH-ER 20 mg/day showed a significant advantage over placebo as early as 1 hour postdose on SKAMP-Combined scores (p < 0.001). When analyzing the entire sample of 54 children, d-MPH-ER maintained significant superiority over placebo from hours I through 12 (p-values ranged from < 0.001 to 0.046). D-MPH-ER was well tolerated, with no severe AEs reported. Conclusions: D-MPH-ER is safe and effective and improves classroom attention, deportment, and performance in children with ADHD.