The study's findings suggest that the expiration dates of some drugs could be safely extended.
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- Study finds many "expired" drugs are just as potent as they were originally made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.
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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."
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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.
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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.