Dexedrine

This is a trademark used for dextroamphetamine sulphate, commonly refered to as "dex." It commonly comes in small heart shaped orange tablets and (spansule-time release) orange and black capsules filled with small beads. This drug is commonly used by college students expecially during finals week, often resulting in post-finals sleep deprivation psychosis.

People often snort dexedrine. If you see someone with orange powder under their nose and they are spun it is likely dexedrine.

Tip: tablets are painless to snort, however, capsules contain sugar and are therefore painful to snort.

Also available in linctus form, like a cough medicine. It is prescribed to habitual amphetamine injecters in the UK, (or it used to be) because there's no way to inject a sugar suspension so it can only be taken orally.

I know this from the personal experience of knowing a guy who injected; he'd sell me the dex linctus in order to buy amphetamine sulphate in powder form so that he could bang it into a vein.

(I think I got the better end of the deal)

The generic or pharmaceutical name used and quoted here as "dextroamphetamine" seems to be one unique to the U.S.A. As far as I'm aware, most other countries use the form "dexamphetamine" usually the sulphate salt, most commonly as 5mg tablets.