Dear Waste Not: That is a great question and one that Lucy has pondered as well. Cleaning out the fridge is easy, because spoiled food is pretty obvious. But now take a peek in the medicine cabinet. That cold medicine from 2005 still looks fine. But is it? For guidance, Lucy turned to MIT Medical’s chief pharmacist, Georgene Bloomfield.
Unfortunately, the answer is far from straightforward. Since 1979, Bloomfield explains, the U.S. Food and Drug Administration (FDA) has required medication manufacturers to stamp every product with an expiration date. This is the date until which the manufacturer can guarantee the drug’s full potency and safety. In addition, she notes, the state of Massachusetts requires pharmacies to label all dispensed prescription medications with an expiration date of no longer than one year.
However, a study done by the FDA and commissioned by the military, which was faced with the prospect of replacing a large and expensive stockpile of drugs every few years, found that even 15 years after the expiration date, most of the 100 drugs tested—both prescription and over-the-counter—showed no significant loss in potency.
But not all of them.
It’s very important to pay attention to the expiration date for certain drugs, notes Bloomfield. “Some products, like tetracycline, may become toxic after the expiration date,” she cautions.
“We know that some drugs, like eye drops and epi pens, used to counteract life-threatening allergic reactions, lose potency rapidly after their expiration dates,” she continues. “Others, like thyroid replacement or blood thinners, have a narrow ‘therapeutic index’—the margin within which the medication is both safe and effective. For drugs like these, even the slightest decrease in potency could cause a major clinical problem for the patient.”
But excluding nitroglycerin, insulin, liquid antibiotics, the medications mentioned above, and, perhaps, a few others, the evidence suggests that most drugs will be safe and relatively effective for some time after their expiration dates. Storing medications in a cool, dry place—or according to the manufacturer’s recommendation— is the best way to maintain potency, Bloomfield adds.
Bottom line when you’re staring down a container of expired Tylenol? If the expiration date was more than a few years ago and it’s important to you that the drug be 100 percent effective, you might want buy a new bottle. But, Bloomfield emphasizes, these are not decisions you need to make on your own. The pharmacists at the MIT Pharmacy are always available to answer medication-related questions from members of the MIT community, so if you have questions or concerns about the safety or effectiveness of any drug, just stop by the first floor of E23 and ask. Bloomfield and her knowledgeable staff are always happy to help! —Lucy