Vyvanse is a prescription medication used primarily to treat attention deficit hyperactivity disorder (ADHD) in both children and adults. It contains the active ingredient lisdexamfetamine dimesylate, which is a central nervous system stimulant. Vyvanse works by affecting chemicals in the brain and nerves that contribute to hyperactivity and impulse control. It is also approved for the treatment of moderate to severe binge eating disorder in adults. Common side effects may include dry mouth, loss of appetite, weight loss, sleep problems, and increased heart rate.