October 01, 2011
Some Canadian researchers studied expired EpiPen auto-injectors 1 to 90 months past the expiration date.
What they found was that the older the EpiPen, the less effective it was due to decreased epinephrine bioavailability. The inverse correlation was 0.63 (months past expiration and decreased epinephrine content).
As long as the solution is clear without precipitates or discoloration, it's fine to use the EpiPen. BUT, still better to use an EpiPen that is not expired!!!
Outdated EpiPen and EpiPen Jr autoinjectors: past their prime? J Allergy Clin Immunol. 2000 May;105(5):1025-30.