Adderall XR, Mydayis and Vyvanse all contain amphetamines and work in a similar way to treat Attention Deficit Hyperactivity Disorder (ADHD). It takes time to work out what drug or drug combinationworks best for you and trial and error is usually required.
Adderall contains four different types of amphetamines (dextroamphetamine saccharate, amphetamine aspartate, dextroamphetamine sulfate, and amphetamine sulfate). It comes in immediate and long acting formulations (Adderall XR).
Mydayis contains similar active ingredients as Adderall XR but is formulated in such a way that its effects last up to 16 hours where as Adderall XR only lasts 12 hours. Mydayis was approved by the FDA in June 2017 for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in patients 13 years and older.
The active ingredient in Vyvanse is lisdexamfetamine. Once lisdexamfetamine is inside the body it gets converted into dextroamphetamine (its active form) as soon as it touches red blood cells. Vyvanse "behaves" like an extended-release form because the contact with red blood cells and the cleaving off of dextroamphetamine takes time.