Epinephrine is a controlled drug. I think it is a chemical form of adrenaline. I'll look it up and post when I get a chance.

The pen allows a person to deliver a dose of epinephrine immediately. One must immediately seek medical care thereafter since the dose may not be sufficient to stop and reverse the effects of the allergic reaction (anaphalaxis (sp?) shock.)

The epi pens are probably not as expensive in England.