Long-Term Safety of OROS Methylphenidate in Adults With Attention-Deficit/Hyperactivity Disorder: An Open-Label, Dose-Titration, 1-Year Study

Objective: To evaluate the long-term safety of OROS methylphenidate in the management of attention-deficit/hyperactivity disorder (ADHD) in adults. Methods: This multicenter, open-label, dose-titration, flexible dose study enrolled adults with ADHD for 6 or 12 months of treatment with OROS methylphenidate. Dosing began at 36 mg/d, with titration in 18-mg increments every 7 days until a predefined outcome (efficacy threshold, maximum dosage of 108 mg/d, or limiting adverse event). Dose reduction occurred for prespecified reasons, and the subjects discontinued if unable to tolerate 36 mg/d. Assessments included ADHD symptoms, adverse events, vital signs, and laboratory results. Results: A total of 550 subjects received treatment (52% were men; mean age, 39 years; range, 18-65 years), and 57% (146/258) and 44% (129/292) completed their 6 or 12 months of treatment with mean durations of 128 and 213 days, respectively. The final prescribed dosages were 36 mg/d (22.4%), 54 mg/d (25.1%), 72 mg/d (22.0%), 90 mg/d (17.1%), and 108 mg/d (13.5%). Modest increases from baseline to final visit were observed in mean systolic (2.6 mm Hg) and diastolic (1.9 mm Hg) blood pressure and pulse (4.1 beats per minute). The mean weight decreased by 2.3 kg. No clinically meaningful changes in laboratory values or electrocardiogram parameters were observed other than increased heart rate. Most common adverse events included decreased appetite (26.7%), headache (24.0%), and insomnia (20.7%). No serious adverse event was considered related to study medication. Several measures of efficacy indicated improvement during the study. Conclusions: OROS methylphenidate, in the flexible dosage range from 36 to 108 mg/d, was well tolerated for up to 1 year in adults with ADHD.