Study Looks At How Hot and Cold Temps Alter Epinephrine

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What if, while attending a summertime family picnic, a food-allergic child shows signs of anaphylaxis.

In a panicked instant, adults realize the child’s epinephrine auto-injectors were left inside a sun-baked car for a few hours, where the temperature far exceeds auto-injector storage recommendations. Will the epinephrine still be effective?

Some researchers, most working at Seattle Children’s Hospital, wondered about scenarios such as this one, and decided to look for answers.

Data Search

Currently, U.S. recommendations for epinephrine storage call for room temperatures of 68 to 77 degrees fahrenheit. When taking auto-injectors on outings, keeping them at 59 to 86 degrees fahrenheit is advised, though this can be tricky for people to monitor or control.

The Seattle investigators combed through research literature looking for studies that exposed epinephrine to temperatures above, at, or below what is recommended. They found nine such studies involving epinephrine in sealed ampules, vials, or syringes, and at concentrations normally used for anaphylaxis or heart resuscitation. Just two of these studies involved auto-injectors.

Findings

Analyzing the results of these nine studies, the Seattle researchers found:

  • Epinephrine deteriorates when exposed to above recommended temperatures, but only with prolonged exposure.
  • Extreme cold did not weaken epinephrine in any of the studies.
  • None of studies looking at the effects of “real-world temperature fluctuations” found significant degradation.

Though the researchers believe more studies are required to assess the effects of temperature extremes on auto-injector devices, they concluded that:

  • Temperature fluctuations “in real-world conditions may be less detrimental [to epinephrine] than previously suggested.”
  • Freezing and limited heat exposure do not cause epinephrine degradation, and refrigerating epinephrine seems to reduce degradation.

Back To The Picnic

Keeping this Seattle research in mind, what if, while attending a summertime family picnic, a food-allergic child shows signs of anaphylaxis, and the child’s auto-injectors have been in a hot car for several hours. Will the epinephrine still be effective?

Though more research details are needed to answer that with any degree of certainty, the Seattle data suggest epinephrine holds its integrity well, deteriorating only when exposed to prolonged high temperatures.

So, in an emergency, if the only auto-injector available has been exposed to extreme heat, it may make the most sense to use it (unless your doctor or allergist advises otherwise)—and call 911.

Source: Annals of Allergy, Asthma & Immunology Photo credit: Claire Gribbin

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