Whatever medicine I give the school to administer to my child at the appropriate times has to be observed; the school cannot wantonly withhold the medications I provide them, especially when provided a Dr's note.
If I send my child to school with an "off-brand" epipen with a doctor's note and direct the school to use this instead, they have to observe it -- a nurse is in no way capable of making a drug administration decision without the consult of a licensed medical doctor.