How long does dextroamphetamine work for?

Depends on the : delivery system.. Dextrostat's onset of action is 20- 60 minutes, peak is ~ 2 hours, duration, ~ 4 hours, requiring multiple daily doses given before the prior dose's effect wears off. Vyvanse (lisdexamfetamine) - ~1 1/2- 2 hrs. for onset, duration 12-14 hours. Mixed amphetamine salts, ~ 1 hr. for onset, duration ~ 5- 6 hrs. if short- & ~12 hrs. if long-acting. Dexedrine Spansules' duration of action is ~ 12 hrs.

4-8 hours: Tablets work for about 4 hours, Capsules work for about 8 hours, if the dose is right for you.