The Food and Drugs Administration have approved Strattera and Vyvanse to treat attention deficit hyperactivity disorder in children and adults. Strattera (atomoxetine) and Vyvanse (lisdexamfetamine) have different mechanisms of action to treat attention deficit hyperactivity disorder (ADHD). Strattera is a nonstimulant drug while Vyvanse is a stimulant. There are some differences in their side effects, dosages, risks, and drug interactions.