While I was performing medication reconciliation, a patient asked me if a beyond-use date is the same as an expiration date. What is the difference?-M.N., N.H.

Jenny Ohler, PharmD candidate 2019, Christopher Miller, PharmD, and Daniel Sheridan, RPh, MS, reply: An expiration date reflects the stability of the product as prepared by the manufacturer; the beyond-use date (BUD) is the last date that a product can be safely used after it has been altered for patient use; for example, by combining it with another drug to create a compounded medication individualized for a patient.1 Common drug alterations include adding water to a medication to make an oral suspension, adding a medication to a bag of fluid to make an I.V. admixture, mixing ingredients together to make a topical cream, and even repackaging a medication outside of its original container.

Expiration dates, which have been legally required on drug products since 1979, indicate the last date at which the manufacturer can guarantee the drug's full potency and safety.2,3 The FDA requires manufacturers to perform various tests on their products to ensure an accurate expiration date. Each product needs to be tested separately due to differences in chemical and physical properties, manufacturing procedures, formulations, containers, and storage conditions. Whether or not the product contains antioxidants or preservatives also influences the expiration date.

However, if a drug is altered in any way-for example, to make an I.V. admixture-the expiration date can no longer be used because it is valid only under the specific conditions tested by the manufacturer. Instead of an expiration date, this type of product requires a BUD, which is similar to an expiration date but typically much shorter.4

BUDs can be based on current scientific literature, manufacturer recommendations, physical and chemical stability, and the risk of microorganism contamination.5 Storing some products in the refrigerator or freezer can extend the BUD by decreasing time for microbial growth. For this reason, many I.V. admixtures are kept in the refrigerator after they are compounded. Keep in mind, however, that some products should not be refrigerated or frozen.

Before dispensing a medication, the pharmacy typically puts a label on the product stating if it requires refrigeration. If a product has no such label or you are unsure, contact the pharmacy for instructions on how to store the product. If you encounter a product that is past the expiration date or BUD, return it to the pharmacy for proper disposal.

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