Like food in the grocery store, medications have specific expiration or beyond-use dates that inform patients of when to replace their drug supply and discard outdated medications. Over time, chemical ingredients making up medications can degrade or react with the environment, changing the potency or chemical composition. Some drugs, such as aspirin, can even degrade into harmful substances past their expiration. Other medications may simply not work as well as the active ingredient decreases. "Expiration dates on medical products are a critical part of determining if the product is safe to use and will work as intended," says Ilisa Bernstein, FDA pharmacist.
The expiration date is the latest date for which a manufacturer can guarantee the medication is safe and effective for use. This is determined from extensive chemical testing. Beyond-use dates are similar to expiration dates, but are applied to compounded or repackaged medications and are determined by both stability testing and U.S. Pharmacopeia (USP) guidelines. If your medication is past the expiration or beyond-use date, it is important to properly dispose of it. Noncontrolled substances can be dropped off at our main hospital and Westwood pharmacy locations, which participate in a drug take-back program. Patients can also throw away medications in the household trash by mixing them in a bag with kitty litter or coffee grounds. Check with your pharmacist for more information about drug disposal and expiration of medications. – Jeffrey Pilz, former pharmacy resident