Amphetamines are drugs that speed up (stimulate) the nervous system. They can raise a person's heart rate and blood pressure. They increase alertness and may create a feeling of euphoria. They can also cause a loss of appetite and trouble sleeping.

Amphetamines may be prescribed to treat conditions such as attention deficit hyperactivity disorder (ADHD) and narcolepsy, a sleep disorder. Common prescription amphetamines include dextroamphetamine (Dexedrine) and methamphetamine (Desoxyn).

Amphetamines can be misused. They may be sold illegally with names such as speed, meth, ice, crystal, and crank.