Hi there, thank for asking. Benadryl is not a good medication for sleeping, although it is sold over the counter as sleep aid. Benadryl can change heart rate as well as vyvance can do. The arousal induced by vyvance will maintain and it is useful to take advantage of some relaxation method like meditation as they do not have any side effect. Vyvance is usually taken in the morning in order not to cause insomnia at night. The dose should be increased gradually in order to minimize the side effects and there should be a reason for it taking (it is usually prescribed by doctors for attention deficit disorder, etc). Otherwise, the side effects would be more than benefits. I wish you the best health.