ADHD treatment with once-daily OROS methylphenidate: interim 12-month results from a long-term open-label study

Few treatment studies of attention-deficit/hyperactivity disorder (ADHD) extend beyond a few months. This article reports an interim analysis of a 24-month study evaluating the 12-month tolerability and effectiveness of a once-daily OROS formulation of methylphenidate (OROS MPH) in children with ADHD.

Children, aged 6-13 years, with ADHD who participated in previous controlled studies and were MPH responders, received once-daily OROS MPH in this multicenter, open-label, nonrandomized study. Effectiveness was evaluated monthly by parents/caregivers and schoolteachers using validated rating scales (e.g., IOWA Conners). Safety and adverse events assessments involved objective (e.g., vital signs, growth) and subjective (sleep quality, tics) reporting.

Seventy-one percent of subjects (289/407) completed 12 months' treatment. Effectiveness was maintained throughout 12 months as demonstrated by stable IOWA Conners ratings and sustained improvements in peer interaction and Global Assessment Scale scores. OROS MPH was well tolerated, with adverse events similar to those expected with short-acting stimulant medication. OROS MPH had minimal impact on sleep quality and tics. There were no clinically meaningful changes in blood pressure, pulse, or height. The apparent absence of meaningful changes is tempered by the fact that children were MPH responders and were medicated at baseline, most for extended periods prior to enrollment.

In this open-label study, once-daily OROS MPH treatment appears to be well tolerated and effectiveness was maintained for up to 12 months in these children with ADHD.