A patient at the primary care clinic where I work took two ibuprofen tablets and soon noticed that the expiration date had passed nearly a year ago. She asked if the medication is still effective. What should I tell her?-W.D., N.C.

Christopher Miller, PharmD, and Dan Sheridan, MS, RPh, respond: Expiration dates are written in a month-and-year format on over-the-counter medications. The date will often be found next to the letters "EXP" on the printed label or stamped in plastic. This tells the consumer that the medication is safe to use and meets manufacturer potency standards until the last day of the printed month and year. The drug may still be just as effective after this date, but the manufacturer guarantees its quality only until the stated date. This date is unique to each drug product and manufacturer due to differences in chemical and physical properties of the active and inactive ingredients, manufacturing procedures, formulations, containers and closures, suggested storage conditions, and other factors. Once a medication is beyond its expiration date, changes in potency, pH, water content, and appearance may render it ineffective. However, this isn't always the case.

Because each drug product is unique, the FDA doesn't have a strict set of rules for setting expiration dates.1 Instead, it publishes broad requirements for expiration dating and stability testing in the Code of Federal Regulations.2

In 1985, the FDA and the Department of Defense started a Shelf Life Extension Program (SLEP) to investigate whether medications stockpiled for the military were still good to use after their expiration dates. Their stability data showed that 84% of the analyzed drug products could be extended beyond their originally labeled expiration date. All the drug products in this program were stored in their original sealed containers at the appropriate temperatures and conditions listed on their labeling.3

While this study may have shown that some drugs remain effective beyond their expiration dates, it included only a small fraction of the thousands of drugs on the market. So, tell patients that after the date printed on the bottle, the medication's quality and effectiveness can't be guaranteed. Even unopened and properly stored medications may be compromised.

Proper storage is just as important to a drug's viability as the expiration date. The drugs used in the SLEP study were all stored in their original containers, at a controlled humidity and temperature, and out of direct light. Inform patients that a medication may be compromised if it's left in a hot car, stored in a humid bathroom, or left out in open air for any amount of time and should not be used. Teach patients to store medications in their original containers in a cool, dry area away from humidity and light. For example, instead of the bathroom cabinet, store medications in a bedroom drawer or kitchen cabinet out of children's reach and where they're less likely to be exposed to humidity.

The bottom line? Advise patients to consult a pharmacist or other healthcare professional before using any questionable medication.

REFERENCES