The expiration date is the final day that the manufacturer guarantees the full potency and safety of a medication. Drug expiration dates exist on most medication labels, including prescription, over-the-counter (OTC) and dietary (herbal) supplements. U.S. pharmaceutical manufacturers are required by law to place expiration dates on prescription products prior to marketing.
For legal and liability reasons, manufacturers will not make recommendations about the stability of drugs past the original expiration date.1 However, for most drugs, it’s just an arbitrary date, usually 2 or 3 years out, that the manufacturer selects to test drug stability. In all actuality, the stability of the drug may be much longer, but no one tests it.
The expiration date of a drug is estimated using stability testing under good manufacturing practices as determined by the Food and Drug Administration (FDA). Drug products marketed in the US typically have an expiration date that extends from 12 to 60 months from the time of manufacturer. Once the original container is opened, either by the patient or the health care provider who will dispense the drug, that original expiration date on the container can no longer be relied upon.2 However, the actual shelf life of the drug may be much longer as stability studies have shown.3
At the pharmacy, “beyond-use” dates are often put on the prescription bottle label given to the patient. These dates often say “do not use after…” or “discard after…” and are required by the Board of Pharmacy in many states. These dates are typically one year from the date of fill. But why would these expiration dates be different? According to the manufacturer, the stability of a drug cannot be guaranteed once the original bottle is opened. Heat, humidity, light, and other storage factors can affect stability. Plus, pharmacies, both retail and hospital, nursing homes, and consumers toss away billions of dollars of medications each year based on stamped expiration dates on stock bottles. In fact, according to a report from Allen9, hospitals alone discard over $800 million in drugs annually.
The United States Pharmacopeia (USP), the body that sets the standards for pharmaceutical quality in the U.S., recommends using “beyond use” dates. The “beyond use” date would never be later than the expiration date on the manufacturer’s bottle.4 However, the expiration date on the prescription bottle from the pharmacy is usually one year from the date it was filled; again, another arbitrary date.