What if someone has anaphylaxis and they are allergic to epinephrine? also, is it possible to be epinephrine resistant?

Impossible: You cannot be allergic to epinephrine. That is impossible. Your body makes Epinephrine naturally and it is necessary to survive. You cannot be Epinephrine resistant. When you are given a shot of epinephrine, it last between 2 and 5 minutes max. So, it will wear off. The point in anaphylaxis is to stop the allergic cascade that happens.

Not possible: I know of no one who is allergic to Epinephrine even though you may get shaking or rapid heart beats from it. However i would take the side effects anytime if I have an anaphylactic reaction. If the anaphylaxis is severe and the treatment is delayed, you may not respond to Epinephrine alone and IV fluid may well be needed.