I'm currently planning out an RPG based on Misfits. Basically young offenders get super powers. I want one of the villains to have a really lame power that they use to become incredibly dangerous. I thought about using a power to caffeinate drinks. If someone used that to super-caffeinate somebody's bloodstream, could that hurt or kill somebody? Or would it not cause any real damage?
In extreme doses, caffeine can - like almost any substance - cause death. Wikipedia has this to say on the subject:
You may wish to consult the references mentioned in the Wikipedia article for further details (As we all know, one should not trust Wikipedia too much). Note that caffeine administrated directly to the bloodstream will be more dangerous than the same amounted ingested.
Information on caffeine toxicity can also be found at Medscape. I you need concrete examples, Holmgreen, Norden-Petterson and Ahlner have published case reports on four recent cases of coffeine-related fatalities. (3)
To cover all bases, it should be said that none of the information mentioned should be used to estimate a safe level of caffeine intake.