The Collaborative International Dictionary of English v.0.48:

Dexedrine \Dexedrine\ n.
   an isomer of amphetamine used as a central nervous system
   stimulant (Dexedrine is a trademark).

   Syn: dextroamphetamine sulphate.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Dexedrine
    n 1: an isomer of amphetamine (trade name Dexedrine) used as a
         central nervous system stimulant [syn: dextroamphetamine
         sulphate, Dexedrine]