Since 1979,US federal law has made it mandatory for drug manufacturers
to place an expiration date on both prescription and over-the-counter
medications. This date, generally two to three years from the date of
purchase, signals the length of time the product can be guaranteed to
maintain full potency and safety in an unopened package. Does this
mean that medications lose their effectiveness or worse yet, become
dangerous after the expiration date?
Definitely not, say most health experts. In a 1985 study conducted by
the FDA at the Air Force's request, more than 100 medications, both
prescription and OTC, maintained full potency for at least three
years, and sometimes even longer. The military commissioned the study
because it was debating how to handle a large stockpile of drugs that
were to expire shortly. And tossing out the drugs was an expensive
prospect. As a result of the study, the military continues to use
certain medications for a period of time after the expiration date.
Why, then, does consumer health information stress the importance of
tossing medications after the expiration date?
According to the pharmaceutical industry, this is because there are
certain medications, such as nitroglycerine (used by heart patients
for chest pain), insulin (used by diabetics to control blood sugar),
and liquid medications such as antibiotics that degrade more quickly
than other medications. This means that some of the effectiveness of
the medication is lost if used past the expiration date – a serious
risk for someone with heart disease, diabetes, or a serious infection.
And while much of the original potency remains in other medications if
used beyond their expiration date, their effectiveness depends in
large part upon how the medication is stored. Most people store drugs
under less than ideal conditions. Drugs degrade more quickly under
warm, moist conditions – exactly the condition found in the medicine
cabinet, on a window ledge, or in the cupboard above the stove.
The bottom line? Nothing magical happens the day after a medication's
expiration date; the drug neither loses all of its potency nor becomes
toxic to use. But to assure maximum efficacy, you should use most
medications before the expiration date. And for best shelf life, store
all medications in a cool, dry place.