Seattle, WA—With a colder than usual November and predictions of an especially frigid winter for much of the country this year, a presentation at the recent American College of Allergy, Asthma and Immunology (ACAAI) Annual Scientific Meeting raised a pertinent question: Will an epinephrine auto injector still work if it freezes?

The devices are carried by millions of patients in the United States who have severe allergies. That means the injectors are often left in cars or carried in purses or pockets during outdoor activities.

“Since many people who live in cold climates use an EAI, we wanted to explore the effects of freezing on how an EAI functions,” explained abstract coauthor Julie Brown, MD, an associate professor in the Department of Pediatrics at the University of Washington School of Medicine and codirector of research for the Division of Emergency Medicine.

For the study, “The Effects of Freezing on Epinephrine Auto-Injector Device Function,” Brown and her colleague 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, the researchers injected the fluid into meat.

Both the meat and devices were weighed before and after freezing. The study determined that the change in meat weight and device weight was similar between frozen-thawed devices and their controls, indicating that freezing did not affect how the EAIs functioned once they were thawed.

Epinephrine is recommended by allergists as the first line of defense in treating anaphylaxis.

“Many people who use EAIs have been concerned about the current shortage of EpiPens,” pointed out allergist Anne Ellis, MD, chair of the ACAAI Anaphylaxis Committee. “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.”

The ACAAI said that pharmacists should advise patients who have an EAI that was unintentionally frozen to use if in an anaphylactic reaction—it’s preferable to use a ‘thawed’ device than nothing at all—but should get a new prescription as soon as possible.

“The study did not examine the amount of epinephrine remaining in the solution after it had been frozen,” Ellis advised in an ACAAI press release. “We know epinephrine is a somewhat unstable compound, and that’s why the shelf life of EAIs is so short.”

 « Click here to return to Weekly News Update.