... tolerance to achieve a high which I did. I only used vyvanse twice my whole life. Later today I will be using benadryl recreationaly 500mg^ im just curious if the antihistamine and amphetamines would cause long term or short term or any damage at all. I know its not safe but ill still probably do It iwant you to be straight foward and tell me if id be fine. Ive last took 100mg of vyvanse at 130 pm yesterday and another 40mg at 4pm. Its now 557 a.m the next day and probably wont use the benadryl until later that night.would I be fine?. It was a 2 day binge I couldn't sleep for 36 hours. I finally got 7 and a half hours a sleep today