Dexmethylphenidate extended release: in attention-deficit hyperactivity disorder

Dexmethylphenidate extended release (XR) is an orally administered, bimodal release, capsule formulation of the active d-enantiomer of methylphenidate (MPH), which inhibits dopamine and norepinephrine (noradrenaline) reuptake to increase their concentration in the extraneuronal space. A single dose of dexmethylphenidate XR mimics the pharmacokinetic profile of two doses of dexmethylphenidate immediate-release formulation administered 4 hours apart, albeit with less fluctuation in plasma concentration. Once-daily dexmethylphenidate XR was more effective than placebo in reducing attention-deficit hyperactivity disorder (ADHD) symptom scores in children, adolescents and adults with ADHD in four randomised, double-blind, placebo-controlled trials of up to 7 weeks' duration. In crossover trials in children (aged 6-12 years), dexmethylphenidate XR 20 mg/day reduced mean ADHD symptom scores 1 hour after administration (by 43% in one trial) and was significantly better than placebo for up to 12 hours. Dexmethylphenidate XR 5-30 mg/day reduced mean ADHD symptom scores by 49%, while scores declined by 16% with placebo in a 7-week trial in children and adolescents (aged 6-17 years). Dexmethylphenidate XR 20, 30 or 40 mg/day reduced ADHD symptom scores by 36-46% versus a 21% reduction with placebo in a 5-week trial in adults (aged 18-60 years). Dexmethylphenidate XR was generally well tolerated in children, adolescents and adults with ADHD, with an adverse-event profile typical of MPH.