A small study published this month showed that most Epipens retain their potency for at least 4 years after their expiration date. That’s no guarantee, of course. I’d still recommend as a “best practice” that families replace them as they expire. But it’s reassuring to know that they’ll usually be effective even when expired. And using an expired EpiPen is almost certainly better than using nothing when there’s a life-threatening allergic reaction.
It’s a simple enough study. Over two weeks, families attending a clinic in California were asked to donate expired Epipens for analysis. They collected 40 devices that had expired up to 50 months before the study, and used state-of-the-art chemical analysis to determine the potency of the medication in the vials. None of them looked discolored or unsafe. All of the pens that had expired up to 2 1/2 years ago had at least 89 percent of their original potency, and even most of the older ones remained in the 85 percent range. Though overall the dose potency slowly deteriorated, all of these devices would have still been helpful to treat an anaphylactic reaction.
A few small previous studies reached similar conclusions in 2015 and 2000. Though these studies looked at the Epipen brand of auto-injectors, it’s likely that studies of similar or generic products would yield the same results.
The authors of the study aren’t recommending that families hoard EpiPens, or delay replacing them — but they do point out that their findings support further studies to extend the labeled shelf life of these products. And if an expired EpiPen is all you’ve got, it’s probably OK to use it as long as it’s not obviously broken or discolored.
To help keep your Epipens in good shape, store them somewhere relatively cool (not cold), and away from light, preferably in the original packaging. Do not leave them in your car in the summer. Epinephrine is a finicky sort of chemical, and light and heat will speed its deterioration. Although you can hold on to expired Epipens as a “backup,” it’s best to replace them, so you’re 100 percent sure that you’ve got what you need when you need it.
Roy Benaroch is a pediatrician who blogs at the Pediatric Insider. He is also the author of A Guide to Getting the Best Health Care for Your Child and the creator of The Great Courses’ Medical School for Everyone: Grand Rounds Cases.
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