Vyvanse (lisdexamfetamine dimesylate) is a prescription medication used to treat attention deficit hyperactivity disorder (ADHD) in children and adults. It is a long-acting stimulant that works by increasing levels of dopamine and norepinephrine in the brain. This can improve attention, focus, and behavior. Vyvanse is typically taken once daily in the morning. It is important to take Vyvanse exactly as prescribed by your doctor. Do not take more or less of the medication than prescribed, and do not take it more often than once daily.