An Epi-Pen is prescribed as emergency treatment for severe food allergies that include anaphylactic shock as a symptom. Epi-Pen is actually a brand name, like Kleenex for a medication called an epinephrine auto-injector. There is now a generic on the market.
The good news is that generic drugs are less expensive, which is particularly good for people without insurance. Epi-Pens are not cheap, and you need to replace them every year.
The bad news is that the generic auto-injector is different from either of the most commonly prescribed brand names, Epi-Pen and Twinject. Your doctor may have prescribed one of these brand name injectors to you and trained you how to use it. Your pharmacy (or rather, your insurance company) may give you the generic injector instead.
Check your injector to see what brand it is, and then look up the instructions for its use. Ask your doctor to prescribe a "trainer" pen - a fake pen used for educational purposes - with each new prescription.
Having a trainer pen is especially important if you have a child with food allergies who has multiple caregivers - babysitters, grandparents, teachers, and the parents of his friends. Everyone who takes care of your child should be trained how to use his injector.
Instructions for each type of injector: