About a few years ago, I had a really bad reaction to caffeine--heart palpitations, rapid heartbeat, high
blood pressure--over drinking a 20oz of
Mountain Dew. I recently started taking Adderall for ADHD (was diagnosed since I was a child but could never swallow medication until early adulthood), and I thought it was really going to mess with my heart. Funny enough, I tolerate Adderall very well with a nominal increase in BP every so often.