Researchers found EpiPens may still deliver an effective dose during an allergic reaction up to four years after their expiration date.

EpiPen past expiration date
Credit: LUCAS TRIEB/AFP/Getty Images

Amid all the bad news, like skyrocketing costs, surrounding epinephrine auto-injector brand EpiPen, a new study published in the Annuls of Internal Medicine Monday reveals some good news: This potentially life-saving medication can be effective long after its expiration date.

CNN reports that after manufacturer Mylan developed less expensive versions of its pens in the wake of the price scandal, researchers looked into how potent and safe expired devices remained. They looked at the epinephrine concentration of 40 expired EpiPens and EpiPen Jrs., and found that 29 months after their expiration date had passed, the pens contained about 90 percent of the medication. Meanwhile, four years post-expiration, 84 percent of the epinephrine remained.

"Essentially, all of these would still be in the recommended therapeutic range," commented Dr. Thomas Casale, executive vice president of the American Academy of Allergy, Asthma, and Immunology. He added, "Until those labels are changed, patients are in a bad situation, because they're concerned about having a life-threatening event and not having a medicine that's effective."

We do not yet know if Mylan plans to change the expiration dates. Meanwhile, it's important to note that lead researcher Lee Cantrell says, "Our paper is not suggesting that people take expired medication."

But the takeaway is this: If your child or someone you know is suffering from an allergic reaction, administering an expired EpiPen is better than nothing, as it likely contains some amount of epinephrine. But you'll obviously want to call 911 as well, and make sure the person gets immediate medical attention. Talk to your child's doctor if you have any concerns or questions about this latest study. And obviously, the best way to treat a life-threatening allergic reaction is to use an EpiPen that has not expired.

Melissa Willets is a writer/blogger and soon-to-be mom of 4. Find her on Facebook where she chronicles her life momming under the influence. Of yoga.