Why not reuse EpiPens with new epinephrine after they expire?

The controversy surrounding skyrocketing prices over the EpiPen emergency allergy shots has nothing to do with what's in the devices. That's the 100-year-old chemical epinephrine, which costs just pennies.

It's the device that Mylan is charging so much for. So why not replace cartridges of epinephrine that have expired with new ones?

Michael Welch, an allergy doctor and professor at the University of California, San Diego School of Medicine, says replacing cartridges is a good idea that doesn't appear to have discussed.

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As of now, it would not be "mechanically possible" to replace the epinephrine, says Welch. Any necessary redesign would probably happen after EpiPens have generic competition next year.

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The severe allergic reaction known as anaphylaxis that EpiPens are used to treat is so serious that doctors, including Welch, pharmacists and insurers worry about alternatives that might not be sterile or precise in the amount of medicine injected

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"In theory it's possible," says Rx Savings Solutions CEO Michael Rea, who is also a pharmacist. "It would require a mechanism to ensure sterility and there may be issues from a cost/benefit over what is currently on the market."

Anaphylaxis can be deadly and symptoms include swelling of the tongue or throat, shortness of breath and a rash.