Timothy E. Wilens, M.D., Department of Child Psychiatry, Massachusetts General Hospital, 15 Parkman Street, WACC 725, Boston, MA 02114; William E. Pelham, Jr., Ph.D., Mark Stein, Ph.D., C. Keith Conners, Ph.D., Howard Abikoff, Ph.D.

Objective: To assess the long-term efficacy and safety of a once-daily OROSR formulation of methylphenidate HCl (MPH) in children with attention-deficit/hyperactivity disorder (ADHD).
Methods: Four hundred seven children with ADHD, ages 6 to 13 years,were enrolled in this open-label, multicenter study. Children received the OROS^® formulation of MPH qd for up to 24 months. All children had participated in previous short-term, controlled studies of the OROS^® formulation of MPH qd. Efficacy was assessed monthly by parents and teachers during the first year and every three months by parents during the second year, using established measures. Adverse events were recorded from parent reports. In addition, parents assessed their child’s tics and sleep quality, and children’s vital signs were monitored throughout the study.
Results: Efficacy ratings showed that treatment efficacy was maintained throughout the 24-month study period. Treatment was well tolerated, with a similar safety profile to that seen in shorter-term studies of the OROS^® formulation of MPH. Adverse events were characteristic of those seen with short-acting MPH treatment.
Conclusions: Once-a-day dosing with the OROS^® formulation of MPH appears to be well tolerated and efficacy was maintained for up to 24 months in this sample of children with ADHD.
This research was funded by ALZA Corporation, Mountain View, CA.