I read an article on research with similar findings about epinephrine validity after exposure to cold for prolonged periods of time.  Let me see if I can find the link:

The article:
http://www.reuters.com/article/us-health-allergy-epinephrine-idUSKCN0PB5R820150701

The research study:
http://www.wemjournal.org/article/S1080-6032(14)00304-4/abstract

I agree that the device itself may be adversely affected, but not necessarily.  As the mechanism for the needle is held with a spring it may have some give if the fluid were to expand when frozen. 

This is compatible with the information DH found from a couple of sources about a year and a half ago, but I didn't have him write it down. But basically it send like it was okay to do mail order Epis in the fall and spring in our state. Not that we've done that.

Impact of Freeze-Thaw Cycling on....

Basically, even after being fully frozen and thawed several times-- for hours-- the EPINEPHRINE solution from an epipen was just fine-- no change or degradation.


That says nothing about possible damage to the device itself, however-- and that could very well occur upon freezing, since the solution containing the epinephrine might well expand and crack the glass, or burst a seal. 

Still, this should be VERY reassuring in terms of temperature excursions at something well above actually freezing (which probably doesn't occur above about 30F or -1C).