Expiry dates for adrenaline autoinjectors may be too short as many retain a high percentage of active ingredient beyond the official 12-18 month use-by date when they are recommended for replacement, US researchers say.
In an evaluation of 46 autoinjectors that were an average of two years out of date, 80% (n = 37) retained more than 90% of adrenaline content. Overall, the ‘expired’ autoinjectors retained an average of 97% of active adrenaline and only nine fell below the FDA’s minimum requirement of 90% adrenaline content, according to a study published in Journal of Allergy and Clinical Immunology: In Practice.
As expected, adrenaline levels were highest in autoinjectors that had recently passed their expiry date.
Those up to six months past the labelled expiration date maintained 100% of the drug, while injectors that were one year past their expiry date showed at least 95% drug content. All the autoinjectors up to 30 months beyond their labelled expiration dates had 90% drug content.
The researchers said the findings had real-world implications when autoinjectors were either in short supply or unaffordable for people at risk of anaphylaxis because they had a food allergy and unstable asthma.
“According to our results, the expiration date of EAIs was set considerably short of the point at which [adrenaline] in the autoinjector drops below the FDA’s required 90%,” wrote study investigator Dr Lynn Kassel of Drake University College of Pharmacy & Health Sciences.
“Extending the expiration dating may allow patients experiencing anaphylaxis access to some medication, particularly during a drug shortage.”
Autoinjectors such as EpiPen were subject to shortages in Australia in 2018, leading the TGA to seek supplies of alternative brands. They currently cost $38 on the PBS or $100 per injector on private prescription.
Current guidelines from ASCIA state that adrenaline autoinjectors should be replaced prior to their expiry date. Expired adrenaline autoinjectors are not as effective as in-date injectors and should not be relied upon to treat anaphylaxis, they advise.
“However, the most recently expired adrenaline autoinjector available should be used if no in-date device is available,” the ASCIA guidelines say.