Background: The objective of this study was to evaluate the safety and efficacy of once-daily OROS methylphenidate (MPH) in the treatment of adults with DSM-IV attention-deficit/hyperactivity disorder (ADHD).
Methods: We conducted a randomized, 6-week, placebo-controlled, parallel-design study of OROS MPH in 141 adult subjects with DSM-IV ADHD, using standardized instruments for diagnosis. OROS MPH or placebo was initiated at 36 mg/day and titrated to optimal response, depending on efficacy and tolerability, up to 1.3 mg/kg/day.
Results: Treatment with OROS MPH was associated with clinically and statistically significant reductions in DSM-IV symptoms of inattention and hyperactivity/impulsivity relative to subjects treated with placebo. At endpoint, 66% of subjects (n = 44) receiving OROS MPH and 39% of subjects (n = 29) [corrected] receiving placebo attained our a priori definition of response of much or very much improved on the Clinical Global Impression-Improvement scale plus a >30% reduction in Adult ADHD Investigator System Report Scale score. OROS MPH was associated with small but statistically significant increases in systolic blood pressure (3.5 +/- 11.8 mm Hg), diastolic blood pressure (4.0 +/- 8.5 mm Hg), and heart rate (4.5 +/- 10.5 bpm).
Conclusions: These results show that treatment with OROS MPH in daily doses of up to 1.3 mg/kg/day was effective in the treatment of adults with ADHD. Because of the potential for increases in blood pressure and heart rate, subjects receiving treatment with MPH should be monitored for changes in blood pressure parameters during treatment.