A study conducted at the Medical University of Lodz, Poland confirms what you already knew: never leave your epinephrine auto-injector in your car on a hot day, because the drug degrades quickly and the device may not administer a sufficient dose when it’s needed.
Researchers purchased a dozen 0.3mg “adult dose” EpiPen brand auto-injectors from the same lot. They placed nine of the devices in the glove compartment, cabin, and trunk of a car parked in a treeless area and the remaining devices in a dark, air-conditioned room at the recommended storage temperature.
Their analysis determined that the epinephrine from the devices stored in the trunk had degraded by 3.3%, 13.3% for those from the cabin, and 14.3% for the devices from the glove compartment.
As the recommended dose of epinephrine for an adult suffering a reaction is 0.3mg, a single exposure can render the effective epinephrine in an auto-injector below recommendations.
The moral of the story: Don’t leave your auto-injector in a car or other hot place.
Here is Mylan’s recommendation for storage of EpiPen:
Storing the EpiPen® Auto-Injector and Its Authorized Generic
EpiPen® and EpiPen Jr® Auto-Injectors and Epinephrine Injection, USP should be stored in the carrier tube provided at a temperature of 20-25 °C (68-77 °F); however, temperature excursions between 15-30 ºC (59-86 ºF) are permitted. EpiPen®, EpiPen Jr®, and Epinephrine Injection, USP Auto-Injectors should not be stored in refrigerators or in a vehicle’s glove box. EpiPen® Auto-Injectors and their authorized generic auto-injectors should not be exposed to extreme heat or cold and should be protected from light.
- Single, short-time exposure to heat in a car during sunny day can decrease epinephrine concentration in autoinjectors: a real-life pilot study – JACI In Practice
- Safety and Storage – Mylan EpiPen Site