A Case of Fatal Nut AnaphylaxisIn March 2013, a teenage college student with a severe nut allergy accidentally ate a cookie containing nuts. He then developed severe anaphylaxis, but his family did not use his Epi-Pen because the expiration date had already passed, and a 911 operator told them over the phone not to use it. While the teen finally did receive an Epi-Pen injection from a neighbor’s device, it was too late: the student died later that evening at a local hospital. (It is important to realize that it is not clear if using the expired EpiPen would have changed the outcome in this tragic event.)
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Food Allergies: A Growing ProblemThe prevalence of food allergies, particularly to peanuts and tree nuts, is on the rise, with rates doubling to tripling in many countries over the past 10 to 15 years. Food allergies, particularly to nuts and seafood, can be severe and life threatening, with more cases of fatal food allergy reactions being reported every year. For the most part, there is no cure for food allergies, although a small number of research centers are performing studies on immunotherapy for certain food allergies, such as peanuts, milk and eggs. The standard treatment for food allergies is avoidance of the culprit food, as well as treatment of allergic reactions that may occur from accidental ingestion of the food.
Epinephrine as the Treatment of Choice for Food AllergiesThe treatment of choice for anaphylaxis from all causes, including as a result of food allergy, is injectable epinephrine. In fact, most cases of fatal anaphylaxis are linked to the lack of, or delay in, the administration of epinephrine. Injectable epinephrine kits come in various brands, including EpiPen, Twinject and Avi-Q. All of these devices have a relatively short shelf life due to the instability of epinephrine: approximately one year from the date of manufacture. Epinephrine breaks down with exposure to light, air and high temperatures. Therefore, manufacturers recommend that epinephrine be stored in a dark place at room temperature, but not refrigerated. Unfortunately, because injectable epinephrine kits are rarely used and are relatively expensive, it's common for people to (knowingly or unknowingly) keep expired epinephrine kits.
Is Expired Epinephrine Still OK to Use?So if it's common for people to have expired injectable epinephrine kits, would it be ok to use them for the treatment of anaphylaxis? This exact question was studied by a group of researchers in Canada and published in the year 2000. The group collected expired EpiPens and determined the potency of the epinephrine contained within them. The potency of the epinephrine was determined by two methods: Taking blood samples from rabbits after they were injected with the expired EpiPens, as well as performing chemical tests on the residual amount of solution left in the EpiPens after they were used. The measurements found in the expired EpiPens were compared to measurements from non-expired EpiPens.
While both methods studied showed that the expired EpiPens contained less epinephrine compared to the non-expired EpiPens, there was still a surprisingly high amount of epinephrine in the expired EpiPens. Even EpiPens that were 5 to 7 years past expiration date still had more than 70% of the original dose remaining in the device. Many EpiPens that were 2 to 3 years past their expiration date had more than 90% of the original dose remaining.
Conclusion: Old Epinephrine is Probably Better than No EpinephrineThe authors of the aforementioned study concluded that it is important to keep non-expired injectable epinephrine available for the treatment of severe allergic reactions, such as those caused by food allergies. There is clear evidence that expired injectable epinephrine kits contain less epinephrine than non-expired kits. However, since expired injectable epinephrine kits – even those that are many years old – contain a significant amount of the original intended dose of epinephrine, they should be used to treat anaphylaxis if there is no other epinephrine available. The potential benefit of receiving a smaller-than-ideal dose of epinephrine would likely outweigh the theoretical danger of using an expired injectable epinephrine kit. (The authors recommended against ever using any injectable epinephrine kit, expired or not, that contains discolored epinephrine or particulates within the epinephrine, for reasons not explained in their study).
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Simons FER, Gu X, Simons KJ. Outdated EpiPen and EpiPen Jr Autoinjectors: Past Their Prime? J Allergy Clin Immunol. 2000;105:1025-30.
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