Heard a bunch of people claiming that there was a study that EpiPens were found to be medically effective well past their expiration date.

Is the claim true, and if so how sound is the study?

  • 3
    This comes down to "what is effective?", but I found an interesting side-effect in this Time article: “The primary concern is that epinephrine will oxidize over time, and because of that, create a byproduct that is associated with hallucinations and other psychiatric symptoms.” It certainly shows that it isn't smart to keep the same EpiPen with you till you need it. May 9, 2017 at 14:58
  • 2
    @Jordy - googling around, the quote used was "the vast majority of the pens we tested were clinically potent"
    – user5341
    May 9, 2017 at 15:00
  • 40
    This really isn't that surprising. The expiration date on things doesn't represent the absolute last date it will be safe. It represents the end of the time period which the manufacturer is confident all units will still be of acceptable quality (assuming proper storage, etc.). Even if a company wanted to find out an exact date, there's probably a good amount of variability just depending on precise details of the production and the care.
    – jpmc26
    May 9, 2017 at 22:32
  • 4
    Common sense says yes. They're not going to immediately stop working on their expiration date. They may just decline in effectiveness past the manufacturer's guarantee.
    – user253751
    May 9, 2017 at 23:43
  • 9
    My understanding of US drug expiration dates is that they are the point the manufacturer promises that the drugs are at least 90% as effective at the time of manufacture, assuming they were stored properly. As this is a low bound, not an average, most drugs will retain more than 90% effectiveness at their date. May 10, 2017 at 2:41

1 Answer 1


Yes, there was such a study, if by "medically effective", you mean something like "better than not using any epinephrine treatment".

From the NIH, a study first published in the Journal of Allergy and Clinical Immunology titled "Outdated EpiPen and EpiPen Jr autoinjectors: past their prime?":

For prehospital treatment of anaphylaxis, we recommend the use of EpiPen and EpiPen Jr autoinjectors that are not outdated. If, however, the only autoinjector available is an outdated one, it could be used as long as no discoloration or precipitates are apparent because the potential benefit of using it is greater than the potential risk of a suboptimal epinephrine dose or of no epinephrine treatment at all.

The linked abstract is pretty clear: the effectiveness does decline, and some units will be discolored or contain particulates, but the data appear to support a conclusion that if you have no other choice, an expired treatment is better than none.

  • 65
    Much like when you're starving, spoiled food is slightly better than no food. Eat the spoiled food, you might get sick. Don't eat the spoiled food, you definitely starve... But that doesn't mean that anyone sane recommends keeping spoiled food around just in case you'll ever find yourself starving. May 9, 2017 at 15:18
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    The thing is, many of the expiration dates on drugs are set for commercial considerations, as well as safety and efficacy. Consider how the exact same drugs can have different expiration dates in the USA and Europe. May 9, 2017 at 19:15
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    @PoloHoleSet Are the differences in expiration date due solely to administrative decisions, or are there differences in any preservatives used?
    – chepner
    May 9, 2017 at 21:05
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    @PoloHoleSet Do the USA and Europe have different standards for how much degradation is acceptable?
    – user253751
    May 9, 2017 at 23:45
  • 12
    Different handling could be an issue when comparing expiration dates between different countries. For example, eggs in Germany are not refrigerated but in the US they are. The difference is that the US relies on cleaning the eggs before sale in order to get rid of any germs, but the cleaning destroys the natural protection of the eggs so you have to refrigerate them, whereas German eggs are not even washed in order to keep the protection intact, so you can store them at room temperature but have to wash them before use. I don't know examples in medicine but it seems plausible that they exist. May 10, 2017 at 11:23

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