I have recently been prescribed Vyvanse and my doctor has started me on 20mg and said he will work me up as needed. Yesterday I took one 20mg pill at 11:30am and found that it felt like it had worn off after only about 3 1/2-4 hours. At 4pm, I tried another pill to see if that would help and it did, but similarly I found that it began wearing off after about 3 1/2 hours and I felt completely unfocused after 4-4 1/2 hours. This morning I tried taking 2 20mg pills at the same time around 10:30am to see if that helped at all. I found it to work much better than the one 20mg pill alone but it felt as though it had worn off by about 5:30pm, roughly 7 hours after taking it, which seems to go along with the results of one 20mg pill lasting about half that time. My questions are, 1) is taking 2 20mg pills equivalent to taking one 40mg pill or are there slight differences between the two ie. the way the medicine is released and over what period of time. 2) would upping my dosage only make me hyper-focused for the same amount of time as the lesser dosage, or will it simply be the same degree of focus for a longer period of time? 3) Is it normal for me to be experiencing the medicine lasting so shortly even though I was told is would last 12 hours? Thank you