Amphetamine is a stimulant and an appetite suppressant. It stimulates the central nervous system (nerves and brain) by increasing the amount of certain chemicals in the body. This increases heart rate and blood pressure and decreases appetite, among other effects. Amphetamine is used to treat narcolepsy and attention deficit disorder with hyperactivity (ADHD). Amphetamine may also be used for purposes other than those listed in this medication guide.