I took Vyvanse starting a month ago. I took it for about 2 weeks and starting getting very tired in the afternoon. I was also having neck, back and joint aches. I stopped taking it and had several days of extreme fatigue. Slept a lot. Had no energy. Took me about a week to recover, but I am feeling much better. Knees and back are not hurting me and I have my engergy back.   I just recently had a blood test done that came back with elevated liver enzymes and I wonder if the vyvanse could have had something to do with it. Had the test last week. never had this elevated level before. Will be running more tests to find out what is going on.