Lisdexamfetamine
"5th month on Vyvanse 30 mg which is on the lower dose end. This med has an awful crash. I exercise 4-6x a week. I eat very healthy. I stay busy. I read so many reviews about the same issue. I did reading about the "minimal" crash felt on this med and it is so scary how pharmaceutical companies try to set the med apart. 
For me it lasts 6 hrs and irritability increases. I think it's in-part tolerance. Mid afternoon, I get severely irritable, anxious, moody, sleepy, and agitated. It is so uncomfortable, I'm supposed to "up" my dose now...to see it last longer and my "crash" will start later"? "