Treatment of Children with Attention-Deficit/Hyperactivity Disorder: Results of a Randomized, Multicenter, Double-Blind, Crossover Study of Extended-Release Dexmethylphenidate and D,L-Methylphenidate and Placebo in a Laboratory Classroom Setting

The purpose of this study was to compare the efficacy and safety of extended-release dexmethylphenidate (D-MPH-ER) to that of D,L-MPH-ER and placebo in children with attention-deficit/hyperactivity disorder (ADHD) in a laboratory classroom setting. This multicenter, double-blind, crossover study randomized 82 children, 6–12 years of age, stabilized on a total daily dose to the nearest equivalent of 40–60 mg of D,L-MPH or 20 or 30 mg/day of D-MPH. Patients participated in a screening day and practice day, and were randomized to 1 of 10 sequences of all five treatments in five separate periods. Treatments included D-MPH-ER (20 mg/day), D-MPH-ER (30 mg/day), D,L-MPH-ER (36 mg/day), D,L-MPH-ER (54 mg/day), and placebo. Primary efficacy was measured by the change from predose on the Swanson, Kotkin, Agler, M-Flynn, and Pelham (SKAMP) Rating Scale-Combined scores at 2-h postdose during the 12-h laboratory assessment (D-MPH-ER 20 mg/day vs. D,L-MPH-ER 36 mg/day). Adverse events were monitored throughout the study period. D-MPH-ER (20 mg/day) was significantly more effective than D,L-MPH-ER (36 mg/day).