By Amanda Gardner, Health.com
updated 4:12 PM EDT, Mon October 8, 2012
STORY HIGHLIGHTS
- Study finds many "expired" drugs are just as potent as they were originally made
- FDA generally requires drugs to contain between 90% and 110% of the active ingredient
- Expired aspirin and amphetamine consistently fell below the 90% threshold
(Health.com) -- Have you ever reached into your
medicine cabinet and pulled out a bottle with a faded label, only to
discover that the aspirin or prescription drugs inside were past their
date? Did you play it safe and toss the bottle into the trash?
If so, you might have been overly cautious. A new laboratory
analysis of eight prescription drugs that expired between 28 and 40
years ago has found that most have remained just as potent as they were
on the day they were made.
Overall, the eight drugs included 14 different active ingredients,
including aspirin, codeine and hydrocodone. In 86% of cases, the study
found, the amount of active ingredient present in the drugs was at least
90% of the amount indicated on the label.
That falls within the range deemed acceptable by the Food and Drug
Administration. The agency allows "reasonable variation" in the strength
of any given batch of prescription drugs, generally requiring that
drugs contain between 90% and 110% of the stated active ingredient.
It's impossible to say from the study results alone whether the
eight drugs would be effective if used today, but "there's no reason to
think that they're not," says Lee Cantrell, the lead author of the study
and a professor of clinical pharmacy at the University of California,
San Francisco.
Two of the tested ingredients, aspirin and amphetamine,
consistently fell below the 90% threshold, as did one sample of the
painkiller phenacetin. On the other hand, three ingredients were found
in amounts greater than 110% of label strength -- perhaps because those
drugs predate quality-control regulations introduced by the FDA in 1963,
the researchers say.
Most drugs are dated to expire after one to five years, but as the
results show, that time frame doesn't necessarily correlate to a drug's
potency, Cantrell says.
"All [the expiration date] means from the manufacturers' standpoint
is that they're willing to guarantee the potency and efficacy for the
drug for that long," he says. "It has nothing to do with the actual
shelf life."
The fact that expiration dates appear to be somewhat arbitrary may
mean that consumers and pharmacies alike are throwing away perfectly
good medicine. And this has important implications for drug shortages
and especially health care costs, the researchers say.
"We're spending billions and billions on medications and medication
turnover," Cantrell says. "If a drug has expired, you've got to throw
it away, it goes into a landfill, and you have to get a new
prescription. This could potentially have a significant impact on cost."
Although consistently taking depleted prescription drugs could
certainly cause complications, expired drugs are generally safe. In the
medical literature there is only one example of an expired drug that
became toxic, and that was an isolated incident, says Cantrell, the
director of the San Diego division of the California Poison Control
System.
The new findings, which were published today in a research letter
in the Archives of Internal Medicine, don't mean you should go digging
through the trash for your expired meds just yet, however.
For starters, some of the drugs tested are no longer widely used,
and it's not clear that the results would be the same for different
drugs, or for similar drugs stored in different conditions, says
Mohammad Nutan, an associate professor of pharmaceutical sciences at the
Texas A&M Health Science Center, in Kingsville.
The drugs in this study were unopened and still in their original
containers, Nutan points out. Medications that are already opened or
those stored in less than optimal conditions might be a different story
altogether, since humidity, temperature, and even exposure to light can
all affect how well a drug stands the test of time, Nutan says.
Still, Cantrell and his colleagues say, the findings suggest that
the expiration dates of some drugs could be safely extended. The FDA, in
fact, has already done so for certain medications in short supply,
including anti-venoms for the Eastern Coral snake and the Black Widow
spider, Cantrell notes.
"Perhaps expiration dating of medications needs to be revisited," he says.
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