麻豆传媒

EpiPen auto-injector retained substantial epinephrine for years after their expiration dates in a small study from California, with more than half of pens tested containing at least 90% of their stated amount of adrenaline.

Researchers tested the potency of 40 expired EpiPen products (31 EpiPens and 9 EpiPen Jrs) collected from a single community clinic over a two-week period. The pens had expired one to 50 months prior to analysis.

Sixty-five percent of EpiPens (1 mg/mL epinephrine) and 56% of EpiPen Jrs (0.5 mg/mL epinephrine) contained at least 90% of the stated amount of the drug, F. Lee Cantrell, PharmD, and colleagues reported in the May 9 issue of .

The findings suggest the need for revisiting the process for determining the shelf life of epinephrine autoinjectors, the researchers said, adding that "in the setting of outpatient anaphylaxis without other therapeutic alternatives, patients and caregivers should consider the potential benefits of using an expired EpiPen."

But in an interview with 麻豆传媒, Cantrell said the take-away message from the study should not be that expiration dates on epinephrine autoinjectors can be ignored.

"The FDA says that most medications marketed in the United States can contain 90% to 110% of the labeled concentration of the active ingredient, and, by that standard, the vast majority of the pens we tested were clinically potent," he said. "But the point is not to encourage people to use expired EpiPens."

In a , many drugs that expired decades earlier (28 to 40 years prior to analysis) retained their full potency when examined.

Cantrell said larger studies are needed to confirm findings from both studies. If confirmed, the findings make a strong case for reconsidering current practices regarding drug expiration dating, he said.

This may be especially timely, he added, given the dramatic price increases of many prescription drugs in recent years.

Last summer, EpiPen manufacturer Mylan angered patients, their families, and public health groups when it raised the price of a twin pack of the auto-injector to more than $600. Critics noted that the actual cost of the epinephrine included in the auto-injector is about $1.

The move proved so controversial that Mylan later announced that it would produce a generic version of the EpiPen at roughly half the cost, but critics complained that this was still too expensive for a life-saving drug with few alternatives.

"If we are trying to save healthcare dollars, and get this drug to the people who need it, revisiting the expiration dating process has broad scale implications," Cantrell said.

He noted that while medications in the U.S. typically have expiration dates of up to three years, EpiPens are often labeled with an expiration date of 18 months or even less.

The study also found that:

• All EpiPens that had expired up to 29 months prior to analysis (n=19) retained 89% or more of the listed epinephrine (range 89% to 100%)
• EpiPens expiring 35 to 49 months before analysis (n=10) retained 84% to 90% of their potency
• Two EpiPens that had expired 50 months prior to analysis retained 88% and 84% of their epinephrine, respectively
• EpiPen Jrs expiring one to two months before testing retained 92% to 99% of their potency
• Two EpiPen Jrs examined seven months after their expiration date had 88% and 91% of their epinephrine remaining
• Three EpiPen Jrs expiring 30 months prior to testing retained 81%, 82%, and 86% of their epinephrine

"Our data show that EpiPen Products can retain substantial amounts of epinephrine well beyond their expiration dates," the researchers wrote. "Although we observed declining concentrations of epinephrine over time, we expect that the dose available 50 months after expiration would still provide a beneficial pharmacologic response."

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