Vivarin are little yellow pills that contain 200mg of caffeine. They are NOT, as the box reads, safer than coffee. I learned this just last week. It is very possible for a person to overdose on caffeine while poppin' Vivarin pills. It's infinitely harder to do the same thing by just drinking coffee -- you simply won't be able to drink 20-30 cups of coffee in an hour. Poppin' 10 Vivarins, however, isn't so hard.
Don't try it, though. You'll puke your damn guts out, and end up in the Emergency Room with an IV in your arm. And then they'll make you swallow activated charcoal. Activated charcoal is NOT cool.