You could also just store a big bag of sugar, just make sure you have something more complex to follow it.
@Cad, it's good for EMS to know all information. Just to use your example, if he is having chest pain, it could be from a multitude of other things besides a heart attack. Even if EMS doesn't think it is important, the ER will need the info. The best thing you can do is to keep the following info and keep it up to date (doesn't need to be in this order):
Past medical history (medical problems)
Previous Surgeries
Medications
Allergies
Any physicians involved in care (PMD, oncologists, surgeons, etc)