Outdated EpiPen and EpiPen Jr autoinjectors: Past their prime?

Background: EpiPen and EpiPen Jr autoinjectors are often recommended for pr ehospital treatment of anaphylaxis. When these units become outdated, there may be a delay in replacing them. Objectives: Our purpose was to evaluate unused, outdated EpiPen and EpiPen Jr autoinjectors, obtained from patients at risk for anaphylaxis, for epine phrine bioavailability and epinephrine content. Methods: We conducted a prospective, randomized, cross-over study of epinep hrine bioavailability after injection from outdated autoinjectors in rabbit s; controls included EpiPen and EpiPen Jr autoinjectors that had not expire d ("in-date" autoinjectors) and intramuscular injection of 0.9% saline solu tion. In addition, the epinephrine content of the outdated EpiPen and EpiPe n Jr autoinjectors was measured by a spectrophotometric method and an HPLC- UV method. Results: Twenty-eight EpiPen and 6EpiPen Jr autoinjectors were studied 1 to 90 months after the stated expiration date. Most were not discolored and d id not contain precipitates. Epinephrine bioavailability from the outdated EpiPen autoinjectors was significantly reduced (P < .05) compared with epin ephrine bioavailability from the in-date autoinjectors. The inverse correla tion between the decreased epinephrine content of the outdated autoinjector s, assessed with an HPLC-UV method, and the number of months past the expir ation date was 0.63. Conclusions: For prehospital treatment of anaphylaxis, we recommend the use of EpiPen and EpiPen Jr autoinjectors that are not outdated. If, however, the only autoinjector available is an outdated one, it could be used as lon g as no discoloration or precipitates are apparent because the potential be nefit of using it Is greater than the potential risk of a suboptimal epinep hrine dose or of no epinephrine treatment at all.