With the 2009 H1N1 influenza scare, the FDA issued an Emergency Use Authorization (EUA) for two antiviral treatments, Tamiflu and Relenza. Although as of 6/23/2010 this EUA has expired, some relevant data regarding the use of medications beyond their expiration date has become available.
Of these two anti-influenza drugs, Tamiflu is by far the more popular among physicians, and is generally easier to use, and so will be addressed here.
Basically, since the concern was that there would not be sufficient in-date medication to go around, the FDA evaluated lots of Tamiflu near or beyond their expiration date for continued safety of use.
These results are regarding Tamiflu still in its original packaging and stored properly between 20-25 degrees C (68-77 F).
By testing representative samples of several lots, the FDA extended authorization for use beyond the original manufacturer’s expiration date up to 6 years for Tamiflu for Oral Suspension and up to 7 years for Tamiflu Capsules.
The tested lots of Relenza were authorized for approximately 6 months extended use.
The data comes from the federal government’s Shelf Life Extension Program (SLEP).
Although one must be careful about generalizing, the data suggest that Tamiflu is safe to use for 6 years beyond the manufacturer’s printed expiration date.
For susceptible strains of influenza, the dosing is 75 mg twice daily for 5 days. It is most effective when started within the first 48 hours of an influenza infection, and may also be used to prevent influenza.
How to ration Tamiflu in times of scarcity will be discussed in a future post.
The FDA report may be found at www.fda.gov/NewsEvents/PublicHealthFocus/usm154962.htm
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