n. a sympathomimetic agent and CNS stimulant that is the dextrorotated form of the amphetamine molecule. It is used in the treatment of narcolepsy and attention-deficit/hyperactivity disorder. Like all amphetamines, it is prone to abuse and dependence. Also called dexamphetamine. U.S. trade names (among others): Dexedrine; Adderall (in combination with amphetamine).