One of my friends has something on her bracelet about having multiple life-threatening allergies to meds and something like "SEE WALLET CARD BEFORE ADMINISTERING ANYTHING". She's very careful to *never* (except at home) be without her wallet, and even at home she keeps her purse easily visible in case an ambulance is required and she can't speak.

The wallet card gives the basic urgent info so they have it faster than calling medilert.