I recently exchanged emails with a fellow who asked if it was acceptable to freeze the auto-injector in his first aid kit.  I told him of course not, you may not have time to thaw the medication.  Now curious, I intentionally froze four expired EpiPens® on a minus 22ºF night and timed how long it took to thaw the auto-injectors in my armpit. 

The first one mechanically fired with a normal amount of pressure while frozen, the needle extended, but no liquid was ejected.  When opened the epinephrine was frozen and there were no obvious cracks in the tubex.  I then thawed the remaining three EpiPens® in my left armpit (97ºF via our household mercury thermometer).   

At 3 minutes I discharged the second EpiPen®, but only a little bit dribbled out of the needle.  I opened this EpiPen® and found the epinephrine still frozen. 

At 4 minutes I discharged the third EpiPen® and I saw a stream of liquid, but it seemed less than expected.  The epinephrine in this unit was partially thawed.   

At 5 minutes I discharged the last EpiPen® and observed a decent steam of liquid and upon opening, found the remaining epinephrine liquid. 

Likewise I froze an ampule of epinephrine.  This was thawed after 3 minutes under my armpit.  The ampule was not cracked.  Several years ago we did the same test on one of the older “AnaGuard” syringes and it took 5 minutes to thaw completely.   

So there you have it, backyard science to support the common sense practice of keeping a liquid emergency medication thawed and ready to use. It makes no sense to tempt fate and hope you can thaw your medication in time. Keep it close to your body in cold weather.

There is a second question here, will frozen and thawed epinephrine work?   If it was frozen and thawed, and I needed it, and it was not discolored with precipitates floating around, I'd use it.  According to the UIAA Medical Commission, yes, it will be biologically active.  However, freeze-thaw is not the best situation and will accelerate the deterioration of the medication.  It can also crack the ampule or syringe and affect sterility of the product.  

Take care

Tod

Kupper, Th. Milledge, J. Basnyat, B. Hillebrandt, D. Schoffl, V  The Effect of Extremes of Temperature on Drugs.  Consensus Statement of the UIAA Medical Commission  Vol 10 2008