Taken from definitions 'round the web.
Adderall - used to treat attention deficit hyperactivity disorder (ADHD) and narcolepsy. It belongs to the family of drugs called stimulants. Also called dextroamphetamine-amphetamine.
Provigil - an analeptic drug manufactured by Cephalon, used for the treatment of narcolepsy, shift work sleep disorder, and excessive daytime sleepiness associated with obstructive sleep apnea.
Nuvigil - Armodafinil (Nuvigil) is a stimulant-like drug produced by the pharmaceutical company Cephalon. Armodafinil is an enantiopure drug consisting of just the active enantiomer of the racemic drug Provigil.
Xyrem - Sodium oxybate is used to prevent attacks of cataplexy in patients who have narcolepsy. Sodium oxybate is in a class of medications called central nervous system depressants.
You can also view a detailed list of pharmacological treatments on the Standford Medicine website.