text: Dexmethylphenidate, sold under the brand name Focalin among others, is a potent central nervous system (CNS) stimulant used to treat attention deficit hyperactivity disorder (ADHD) in those over the age of five years. It is taken by mouth. The immediate release formulation lasts up to five hours while the extended release formulation lasts up to twelve hours.  It is the more active enantiomer of methylphenidate.  
  Common side effects include abdominal pain, loss of appetite, and fever. Serious side effects may include abuse, psychosis, sudden cardiac death, mania, anaphylaxis, seizures, and dangerously prolonged erection. Safety during pregnancy and breastfeeding is unclear. Dexmethylphenidate is a central nervous system (CNS) stimulant. How it works in ADHD is unclear.
  Dexmethylphenidate was approved for medical use in the United States in 2001. It is available as a generic medication. In 2021, it was the 121st most commonly prescribed medication in the United States, with more than 4million prescriptions.