I began 20mgs of Adderall XR/daily a couple weeks ago. I have had several smaller side effects since the beginning including: appetite suppression, changes in sexual ability/desire and slightly increased heartrate (i'm a runner so my heartrate is about 80bpm resting, but 30 - 40 bpm faster than normal) additionally, I sweat more while on adderall. Very recently, I noticed a weird sporadic feeling in my body. i began monitoring my pulse and it seems like my pulse would skip a beat here and there. I haven't taken a dose of adderall since then (Thursday March 27, 2008) and today (Saturday March 29, 2008) the phenomena seems to have ceased. I am going to the Dr. tomorrow and tell him this. My question is three fold: 1) how common is it for adderall to cause heart palpitations? 2) how serious are palpitations? and 3) should I dose as prescribed on Monday before going to the Dr. such that if the palpitations are a problem, that they might recur for diagnosis?