Methylphenidate, sold under the brand names Ritalin ( RIT-ə-lin) and Concerta ( kən-SUR-tə) among others, is a central nervous system (CNS) stimulant indicated in the pharmacotherapy of attention deficit hyperactivity disorder (ADHD) and narcolepsy. It may be taken by mouth or applied to the skin, and different formulations have varying durations of effect...