Where to buy Phenida . Methylphenidate is a central nervous system (CNS) stimulant of the phenethylamine and piper dine classes that is use in the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy. Methylphenidate has been in study and research for over 50 years. And it has a very good efficacy and safety record for the treatment of ADHD. The original patent was own by CIBA, now Novartis Corporation. It was first license by the U.S. Food and Drug Administration (FDA) in 1955 for treating hyperactivity.