© 2016 Roy Benaroch, MD
The sticker shock for Epipen purchases has some people wondering: Do I really have to buy a new one every year or so? Does it really matter if the drug has aged past its expiration date?
An Epipen is a device that automatically injects epinephrine. It is The Drug for potentially catastrophic allergic reactions to things like foods or bee stings. If someone’s having a bad reaction, epinephrine can save a life. In a medical situation, we’d typically draw up epinephrine from a little vial (which is way cheap, less than 5 bucks) and inject it into an available big muscle. Presto, you’re in the clear (it really can work super-quickly. Quite satisfying.) Since it’s awkward and perilous to draw up epinephrine into a syringe while you or your child is dying of an allergic reaction, for home use an automatically-injecting device is prescribed. Handy! Just remove a cap, press against the skin, and a little spring loaded mechanism fires off, poking out the needle and injecting the medicine in one E-Z step.
Those autoinjectors were first developed by the US military for treating nerve gas attacks. By the mid-1970’s a home version for allergies came out, and though the company that developed it has changed hands, merged, and moved on, the thing that’s currently sold uses pretty much the same technology. The medicine in there, epinephrine, is (and has been) dirt cheap for decades. What makes an Epipen expensive is the device used to inject it, which is currently protected by both patent law and an FDA that seems keen on making sure it’s the only widely available brand. Free from any competition, and with sales buoyed by aggressive marketing, by the manufacturer has been jacking the price through the roof.
Making this even more expensive: a newly purchased Epipen has a manufacturer’s expiration date, typically less than 2 years after purchase. So what happens after that date? Does the medicine really “go bad”?
There aren’t a lot of studies about this. I found two (thanks very much to the Simons, both F. Estelle and Keith, from Winnipeg, Canada – they’re authors on both papers!) In May, 2000, the Simons examined 34 donated Epipen injectors, administering them to 6 New Zealand White rabbits (not at the same time.) The out-of-date injectors delivered less epinephrine, and the drop was proportional to the age past expiration. The older the device, the more it lost its punch. Still, eyeballing their data in Figure 2, devices that were less than 24 months past expiration had between 60-90% of their drug intact, which isn’t terrible. They concluded that as long as the epinephrine wasn’t visibly discolored or damaged, it was better to use an expired Epipen than nothing at all.
Those same authors (with a few extra friends, minus the rabbits) looked at expired Epipens again in 2015, measuring potencies of 80-100% in devices up to three years past their expiration. Again, not too shabby.
Epinephrine is especially vulnerable to breaking down in heat. Epipens stored in car glove boxes aren’t going to last. And the auto-injecting mechanism, while robust, isn’t made for kickboxing practice or roller coaster festivals.
Still, for ordinary households who try to keep their Epipens in a cool, the devices probably keep at least some potency somewhat past their printed expiration dates. It’s best if families replace them after they expire, to make sure they’re getting a full and reliable dose. But if someone needs a dose of epinephrine, and the only Epipen you’ve got is expired – use it.
And when you do buy a new one, make sure to ask the pharmacist to give you the new stuff, even if she has to reach way in the back. Since they’re so expensive, it might even be worth it to call around a few places, to see whose stock is the freshest.
More about drug expiration dates