Whether it's over-the-counter cold medicine or a prescription drug, expiration dates on medications generally indicate when the med will start losing its potency or effectiveness. In general, Dr. Mackey said, the expiration dates printed on your medication are pretty conservative measurements. "Many maintain good potency after their expiration dates," he said, so some drugs and medications might still work well for a few years after that printed date.
Still, in most cases, it's better safe than sorry. This is especially true, Schwemm said, when it comes to prescription drugs. The older the drug is — the closer to, or farther past, its expiration date — the more it starts degrading, and the less actual drug product there is. "If it's medication where you really need the effect, where you really need it to work — whether it's birth control or blood pressure medication — I would want that to work 100 percent," she explained.
Plus, studies don't look at what happens to the drug when it breaks down, post-expiration date. "The likelihood that it's turning into something negative is very low," Schwemm said, "but researchers also aren't testing for it, so we don't really know what the drug has potentially degraded into."
They both advised doing extra research into your specific medication. It's free to consult a pharmacist, Schwemm reminded us, and you can also check in with a doctor. "My recommendation would be, where possible, always just get your doctor to write you a current prescription and get it filled," Dr. Mackey told POPSUGAR.