I'm 57 and just diagnosed with ADD (inattentive) and suddenly my life makes sense! My doctor put me on 20mg of Vyvanse and today is my second dose. I definitely felt better until about 2pm yesterday at work (took my dose at 5:30am) but then I became very tired & unfocused. I also noticed a big increase in joint pain, especially my knees which I have osteoarthritis in anyway, I have been googling about joint/muscle pain as a side effect and have seen a few reviews etc commenting about this but what I'm wondering is if this is a side effect that will calm down after a while? Its difficult to walk with this amount of discomfort & the main reason I wanted to take the Vyvanse was to make me more productive at work & home which is hard to do when you're in pain