The combination of dextroamphetamine and amphetamine (Adderall, Adderall XR, Mydayis) is used as part of a treatment program to control symptoms of attention deficit hyperactivity disorder (ADHD; more difficulty focusing, controlling actions, and remaining still or quiet than other people who are the same age). Adderall is used to treat ADHD in adults and children 3 years of age and older. Adderall XR is used to treat ADHD in adults and children 6 years of age and older. Mydayis is used to treat ADHD in adults and children 13 years of age and older. Dextroamphetamine and amphetamine (Adderall) is also used to treat narcolepsy (a sleep disorder that causes excessive daytime sleepiness and sudden attacks of sleep) in adults and children 12 years of age and older. The combination of dextroamphetamine and amphetamine is in a class of medications called central nervous system stimulants. It works by changing the amounts of certain natural substances in the brain.
The combination of dextroamphetamine and amphetamine comes as an immediate-relase tablet (Adderall) and as an extended-release (long-acting) capsule (Adderall XR, Mydayis) to take by mouth. The immediate-release tablet (Adderall) is usually taken 2 to 3 times daily, 4 to 6 hours apart, with or without food. The extended-release capsule (Adderall XR) is usually taken upon awakening with or without food. The extended-release capsule (Mydayis) is usually taken upon awakening and must be taken consistently either with or without food. Dextroamphetamine and amphetamine combination should not be taken in the late afternoon or evening because it may cause difficulty falling asleep or staying asleep. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take dextroamphetamine and amphetamine exactly as directed.
Summary from MedlinePlus.gov, click for more information.