Single-dose pharmacokinetics of multilayer-release methylphenidate and immediate-release methylphenidate in children with attention-deficit/hyperactivity disorder.

The objective of this study was to compare the single-dose pharmacokinetics of multilayer-release and immediate-release methylphenidate in children with attention-deficit/hyperactivity disorder. Patients 6- to 12-years-old with a DSM-IV diagnosis of attention-deficit/hyperactivity disorder were randomized to receive multilayer-release methylphenidate (qd) or immediate-release methylphenidate (bid) at equivalent doses, with a 14-day washout between treatments. Plasma samples were collected predosing and 1, 2, 3, 4, 5, 6, 8, 10, 12, and 24 hours postdose. Pharmacokinetic analysis was conducted on 14 patients (1 female, 13 male; mean age: 9.6 +/- 2.5 years [range, 6-12]). The mean dose of methylphenidate received by these patients in both phases of the study was 38.6 mg/d (range, 20-80 mg/d). The relative AUC(0-t) and C(max 0-4) ratios for multilayer-release compared with immediate-release methylphenidate were 100.8% and 78.8%, respectively. Multilayer-release methylphenidate produces a biphasic concentration-time profile, with a rapid initial increase in plasma concentration that is maintained throughout the school day.