APA Dictionary of Psychology

n. a CNS stimulant, closely related in structure and activity to ephedrine (see ephedra), that is the prototype of the group of drugs known as the amphetamines. Amphetamine is a chiral molecule, composed of two stereoisomers (mirror images): levoamphetamine and dextroamphetamine. Specific amphetamines may be racemic mixtures of both stereoisomers (U.S. trade name: Benzedrine.