Will an EpiPen Still Work if It Freezes?

An EpiPen can save the life of someone in anaphylactic shock. But if the epinephrine inside freezes, is the pen still viable? Joe Raedle/Getty Images

The winter season is finally in full swing, and while the steady stream of snow, sweet treats and holiday fun can be rewarding, for those with a severe allergy, this time of year can be tough. It's not just the abundance of potentially triggering foods that's concerning, those frigid temperatures can also mean that anyone required to carry an epinephrine auto injector (EAI, or EpiPen by brand name) has to contend with cold weather and its possible effects on their medication.

What we mean is what happens if an EpiPen user leaves their anaphylaxis treatment exposed to the elements, say in their car and it freezes? Will an EpiPen that freezes still work?


According to research presented at the American College of Allergy, Asthma, and Immunology (ACAAI) Annual Scientific Meeting in November 2018, the answer is yes ... but that doesn't mean you should stock supplies in your kitchen.

"Since many people who live in cold climates use an EAI, we wanted to explore the effects of freezing on how an EAI functions," abstract author, Julie Brown, M.D., explained in a statement. "Lead author and researcher Alex Cooper took 104 same-lot pairs of EAIs and froze one of each pair for 24 hours, while the other was kept at recommended temperatures as a control. Once the frozen devices were thawed, they and their controls were injected into meat."

The scientists had a sneaky way of assessing whether or not the EAIs remained viable: They weighed the meat and the devices before and after injections. Because the change in weight for both the meat weight and device weight remained pretty much the same between the devices that were frozen/thawed and the controls, the researchers could confirm that freezing hadn't affected the function of the EAIs. Why? Because both meats seemed to get the same amount of medication, regardless of whether the EpiPen had been frozen or not.

"Many people who use EAIs have been concerned about the current shortage of EpiPens," allergist Anne Ellis, M.D., chair of the ACAAI Anaphylaxis Committee, said in a statement. "It's important for those who have severe, life threatening reactions to their allergies to have confidence in the EAIs they carry and know they'll work in an emergency. This study showed that even when an EAI has been unintentionally frozen, the risk is low that it will malfunction."

All that said, experts still advise against intentionally freezing your EAI for any reason. For one thing, just because the devices still worked, this study didn't confirm that the contents was still totally intact. The test was only able to look at whether the freezing would affect the mechanics of an epinephrine auto-injector. "It didn't look at whether it impacted the quality of the epinephrine in the device," Ellis told Medpage Today. "It's reassuring to know that it will still fire if it accidentally freezes, but it may not be delivering a full dose of fully active epinephrine."

While it's better to use an accidentally-frozen-and-thawed device than nothing at all in case of anaphylaxis, the limitations of the study make it tough to know if longer freezing time or repeated freezings could cause damage. "The study did not examine the amount of epinephrine remaining in the solution after it had been frozen," Ellis said in the statement. "We know epinephrine is a somewhat unstable compound, and that's why the shelf life of EAIs is so short."

Bottom line: Always work closely with an allergist who can help guide your treatment — and be kind to your EpiPen in case you ever need it.