Objective: This study aimed to compare the effects of dexmethylphenidate (D-MPH) extended-release (ER) 30 mg and D-MPH-ER 20 mg on attention, behavior, and performance in children with attention-deficit/hyperactivity disorder.
Methods: In a randomized, double-blind, 3-period-by-3-treatment, crossover study, children aged 6 to 12 years with attention-deficit/hyperactivity disorder stabilized on methylphenidate (40-60 mg/d) or D-MPH (20-30 mg/d) received D-MPH-ER 20 mg/d, 30 mg/d, and placebo for 7 days each (final dose of each treatment period administered in a laboratory classroom). Swanson, Kotkin, Agler, M-Flynn, and Pelham (SKAMP) Combined (Attention and Deportment) rating scale and Permanent Product Measure of Performance (PERMP) math test assessments were conducted at baseline and 3, 6, 9, 10, 11, and 12 hours postdose.
Results: A total of 165 children (94 boys; mean age, 9.6 years) were randomized (162 included in intent-to-treat analyses). Significant improvements were noted for D-MPH-ER 30 mg over D-MPH-ER 20 mg at various late time points on the SKAMP scales (Combined scores at 9, 10, 11, and 12 hours postdose; Attention scores at 10, 11, and 12 hours postdose; deportment scores at 9 and 12 hours postdose). The PERMP math test-attempted and -correct scores (change from predose) were significantly higher with D-MPH-ER 30 mg than with D-MPH-ER 20 mg at 10, 11, and 12 hours postdose. Both D-MPH-ER doses were superior to placebo at all time points.
Conclusions: D-MPH-ER 30 mg was superior to D-MPH-ER 20 mg at later time points in the day, suggesting that higher doses of D-MPH-ER may be more effective later in the day.