ADouble-Blind, Placebo-Controlled Withdrawal Trial of Dexmethylphenidate Hydrochloride in Children with Attention Deficit Hyperactivity Disorder

Objectives: d,l-threo-methylphenidate HCl (d,l-MPH) is the most common treatment of attention deficit hyperactivity disorder (ADHD). A previous report showed placebo-controlled efficacy for the purified d-isomer (dexmethylphenidate hydrochloride, d-MPH, Focalin™) with a 2:1 potency compared to dl, and suggested a 6-hour duration of action. This study complements that report by studying the effect of placebo-controlled discontinuation and retesting the duration of action. Methods: A 6-week, open-label titration of d-MPH (2.5–10 mg twice-a-day) was followed by a double-blind, placebo-controlled, 2-week withdrawal study of responders. Results: In the open titration, 82% of the 89 enrolled patients achieved a Clinical Global Impression—Improvement (CGI-I) rating of much or very much improved. Only 5 patients discontinued for adverse events. Seventy-five patients continued into the placebo-controlled discontinuation. For the randomly assigned d-MPH (n = 35) and placebo (n = 40) groups, mean ages, respectively,...