Dear Dr. K: I keep an Epipen for “just in case,” but so far I have never had to use it. I keep replacing it when it expires, but it is expensive. Is it possible to use it past its expiration date?
The answer is “yes, probably.”
The “probably” is based on the clarity of the liquid. If, when you look through the syringe and the medicine is clear, then it’s both safe and effective. If the liquid is yellow or cloudy, then discard it.
The Medical Letter, which is a nonprofit academic resource for physicians and hospitals seeking non-pharmaceutical company-biased information, actually addressed these issues in their December issue. They actually cited their research studies done on epipens.
The first study looked at pens that were from 1 to 90 months past their expiration. This showed a percentage reduction in potency correlated with the number of post-expiration months; i.e., pens one-month past expiration had 1 percent reductions in potency, while pens 90 months past had 90 percent reductions.
A second study evaluated pens 36 months past expiration and found them to be from 84 to 100 percent potent.
A third study looked at epipens stored on EMS vehicles that were from one to 11 years expired. These devices retained from 3 to 31 percent of their potency. The Medical Letter pointed out that exposure to greater heat in the ambulances will speed the degradation of the active medicine.
Data from the U.S. Department of Defense/FDA Shelf-Life Extension Program, which tests the stability of drugs past their expiration dates, showed that in a study of 3,000 different drugs 88 percent of them remained stable and fully active 66 months past expiration. High heat and humidity do accelerate degradation of many drugs.
This publication did say that ophthalmic (eye) medicines should never be used beyond expiration, even though the medication may be stable, because bacterial contamination occurs with repeat use. Authors also pointed out that certain dry powder inhalers such as Advair Diskus slowly absorb moisture once the device is removed from its foil container. This “gums up” the delivery in devices past expiration.