Are drug expiration dates meaningless?

It's late, and someone in your house has a headache, a stuffy nose, or — oh no, was that the sound of retching? You rifle through your home's jumble of medications, quietly pumping your fist in the air when that bottle of Tylenol or Pepto-Bismol finds your hand.

It's only then that you notice the expiration date: It was last month, last year, last decade. You realize you don't know what that actually means — whether the drug you're holding is dangerous or merely ineffective, and whether you'd cause more harm by using it or withholding it.

What now?

For many, medicine expiration dates are a source of fear and doubt. Whether it's an over-the-counter fever reducer or a critical prescription heart medication, knowing how to evaluate the risk of taking it — or not taking it — can save you a lot of worry. Here's what you need to know about how medications age.

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Email (required)By submitting your email, you agree to our Terms and Privacy Notice . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. The US Food and Drug Administration only began requiring drug manufacturers to put an expiration date on medications in 1979 . However, they didn't tell companies how to come up with those dates. Most companies didn't opt to do the expensive work of methodically testing each drug during development to determine the exact age at which it began degrading. Instead, most simply chose dates a few years out, tested the drug's potency at that time, and if it was still as good as new, called that the expiration date.

That is to say, drug expiration dates aren't "bad after" dates as much as they are "good before" dates. For most drugs, these dates are set to about three years after the day they're produced, says Lee Cantrell , a pharmacist and toxicologist who also directs operations at the San Diego division of the California Poison Control System.

However, many drugs retain much of their potency for a lot longer than three years. In 2012, Cantrell and several of his colleagues tested a range of drugs (including acetaminophen, the sedative phenobarbital, and the opioid hydrocodone) that were decades past their expiration dates, and found that 86 percent of them still had the intended concentrations of their active ingredients. A few years later, a group of German researchers conducted a similar study with similar results.

One of the German researchers, Ulrike Holzgrabe , a pharmaceutical chemist at the University of Würzburg, told me these findings suggest drug companies should be determining expiration dates more rigorously. "After the licensing of a drug, the companies should store the drugs for another 10 years" and analyze them annually for stability, she said.

There's an obvious disincentive for manufacturers here, says Cantrell: Proving that certain products have much longer shelf lives than we assume would mean less frequent re-upping, which would decrease sales. Some manufacturers may actually have done studies proving their products last well beyond their expiration dates — but "there's no way they'd ever release that data — it's just not in their interest," says Cantrell.

Replacing drugs that are still effective is wasteful and expensive. In an effort to make better use of their drug supplies, federal agencies that stockpile drugs — like the military or the Department of Veterans Affairs — asked the FDA to extend the official shelf life of several drugs in the 1980s. The agency developed the Shelf-Life Extension Program to do exactly that by batch-testing key medications on the brink of expiring.

Still, these extensions happen only on a case-by-case basis — and only for pharmacies run by government institutions. Although expiration dates don't accurately represent the true lifetime of a drug, the system we have right now doesn't account for that.

Drugs change with age, but not in the way you might fear Part of the problem with medication expiration dates is that it's hard to tell with the naked eye whether most drugs are past their prime. "A drug is not a yogurt or a piece of meat or a strawberry," says Holzgrabe. Experts nevertheless have a sense of the kinds of invisible changes drugs are likely and unlikely to undergo after a certain period.

For starters, pharmaceuticals don't typically turn into poison as they age. "I'm not aware of any medications that become toxic once they pass their expiration date," says Cantrell. That means you typically don't have to worry that an expired drug will make you sick. However, because some drugs do lose potency over time, expired drugs may do some harm by not working the way you expect them to.

It's hard to tell with the naked eye whether most drugs are past their prime. "A drug is not a yogurt or a piece of meat or a strawberry."

With time, there may also be changes to the integrity of some drugs' inactive ingredients. These are the medication additives that get drugs' active ingredients where they need to go or make them palatable for the consumer. For example, a skin cream used for eczema might separate or change in texture over time, or a suppository containing fever medicine might melt. Conversely, liquid formulations can slowly condense as the water and alcohols in them evaporate. This means a shot from that older bottle of NyQuil could theoretically be stronger than it's supposed to be.

Sometimes, time can render a drug's delivery system ineffective, making it impossible for you to access the actual medication inside it. This is the same concept that results in an old can of hairspray being unusable even if there's still plenty of product left inside: Medications that rely on propellants — like itch-control sprays or the albuterol rescue inhalers people use to control asthma symptoms — often become useless when their containers are too old.

It's not just the years that change our medications' potency: The way they're stored can also have an impact. Exposure to sunlight, heat, and moisture all degrade drugs more quickly. These exposures can also facilitate microbial overgrowth, even in unexpired medications. Although this risk is more related to unsafe drug storage than it is to a drug's age, it's one worth being aware of. That's especially true for medications that are intended to be sterile, like eyedrops , as contamination can lead to permanent eye damage in people who use these products.

How to manage household medications to minimize worry To keep drugs from losing potency before their time and reduce the likelihood they'll be overrun with germs, Holzgrabe recommends storing them in the bedroom — not in the bathroom or in the kitchen, where they're more likely to encounter heat and humidity.

The safest approach is to keep only unexpired drugs in your household — especially when it comes to critical, life-saving medications like antibiotics, blood thinners, EpiPens, asthma rescue inhalers, insulin, and the like. The FDA recommends consumers regularly take stock of what they have on hand and toss expired medications . The agency also provides recommendations for how to safely dispose of different types of drugs.

That said, if you find yourself in an emergency situation where you only have an expired version of a life-saving medication and you can't immediately get a fresh supply, use the medication you have — so long as it doesn't delay getting the sick person emergency care. "If someone called me and asked me and said, 'This is all I got and I'm having trouble breathing and all,' I'd say, 'Use it,'" says Cantrell.

The truth is, experts say they do often use expired over-the-counter medications in non-emergency situations at home — if they have a kid with a cold, for instance. However, it's not something they can recommend to others; there simply needs to be more rigorous testing of medications before they can give that kind of broadly applicable advice.

Although drugs may have longer shelf lives than their packaging says, it shouldn't be on consumers to guess which ones might still be effective. Instead, manufacturers should be studying each newly licensed drug to determine its actual expiration date by storing quantities of it and testing its stability on an annual basis, says Holzgrabe. Tighter regulation of the pharmaceutical industry would help, she says: "The law has to be changed so that we do not throw away so many drugs which are still okay."