Objective: The aim of this study was to compare efficacy and safety of two long-acting formulations of methylphenidate (MPH) for attention-deficit/hyperactivity disorder (ADHD) in school-age children.
Methods: Children 6–12 years of age diagnosed with ADHD and stabilized on MPH (20–40 mg/day) participated in a five-way, randomized, placebo-controlled, single-blind, crossover study conducted in a laboratory classroom setting. Children alternately received single doses of extended-release MPH (ER-MPH) 20 and 40 mg, modified-release MPH (OROS-MPH) 18 and 36 mg, and placebo over 6 consecutive weeks. Efficacy was assessed using SKAMP rating subscales and written math tests. Data were examined using between-treatment comparisons of area under the curve (AUC) for change from predose values during hours 0–4, 0–8, 8–12, and 0–12. Safety was assessed.
Results: Fifty-three children completed the study. For all efficacy measures, improvements from predose were significantly greater with ER-MPH 40 mg than with OROS-MPH 36 mg in terms of AUC0–4 (p ≤ 0.005), AUC0–8 (p ≤ 0.006), and AUC0–12 (p ≤ 0.035). For most measures, ER-MPH 20 mg was equivalent to both doses of OROS-MPH in AUC0–4, AUC0–8, and AUC0–12. No serious adverse events were reported.
Conclusions: The efficacy of ER-MPH 20 mg is similar to that of OROS-MPH 18 and 36 mg during the first 8 hours postdose. Statistically greater benefits are observed with ER-MPH 40 mg than with OROS-MPH 36 mg and persist through hour 8. Active treatments show comparable efficacy from 8 to 12 hours postdose. Both doses of each MPH formulation are well tolerated.
