Tirzepatide, a medication classified as a GLP-1 and GIP receptor agonist, is frequently prescribed for the management of type 2 diabetes and chronic weight management. When it is prepared by a specialized facility, it is referred to as “compounded tirzepatide,” meaning the medication is custom-made for an individual patient. This preparation is distinct from commercially manufactured versions and raises important questions about its shelf life and stability. Since compounded medications are not subject to the same extensive testing as mass-produced drugs, they do not have a standard expiration date, leading to a different set of rules for how long they can be safely used.
Compounded Medications and Stability Testing
Commercial drug manufacturers must conduct years of formal, long-term stability studies to determine a precise expiration date for their products. These studies involve testing the drug’s potency and purity under various conditions over extended periods, with the results reviewed and verified by the Food and Drug Administration (FDA).
Compounded medications, such as injectable tirzepatide, are prepared on a smaller scale by state-licensed pharmacies to meet a patient’s specific needs, which may involve altering the drug’s form or strength. Because these custom preparations are not identical to the commercially available drug, they do not undergo the same long-term stability testing to establish a multi-year expiration date. This difference necessitates a different dating standard to ensure the medication remains safe and effective for the patient. The lack of extensive stability data means that the date assigned to a compounded drug must be more conservative than a typical commercial expiration date.
Defining the Beyond Use Date
The definitive answer to whether compounded tirzepatide “expires” is found in the term Beyond Use Date (BUD). The BUD is the date after which a compounded preparation must not be used, stored, or transported, and it is determined by the compounding pharmacist. The BUD is not interchangeable with a manufacturer’s expiration date, as it accounts for both the chemical stability of the drug and the risk of microbial contamination.
Pharmacists establish the BUD based on standards set by the United States Pharmacopeia (USP), specifically USP <797> for sterile preparations like injectable tirzepatide. These guidelines provide a framework for assigning a conservative date in the absence of long-term stability testing data. For compounded sterile preparations, the assigned BUD is typically a much shorter duration, often ranging from 30 to 90 days from the date of preparation, assuming proper storage. Once the vial has been punctured for the first dose, a new, even shorter time limit, such as 28 days, may apply to the remaining doses in the vial, whichever is sooner than the original BUD.
Guidelines for Storage and Handling
Maintaining the potency and safety of compounded tirzepatide requires strict adherence to specific physical storage instructions until the assigned BUD. As a peptide, tirzepatide is sensitive to heat, light, and freezing, which can cause the molecule to degrade. The primary requirement for storage is continuous refrigeration within a narrow temperature range, typically between 36°F and 46°F (2°C to 8°C).
The medication should be stored in the main body of the refrigerator, away from the freezer compartment, to prevent accidental freezing, which can irreversibly damage the drug. Protection from light is also important, so the vial should be kept in its original packaging when not in use. If the medication must be transported, it should be kept in a cold environment using an insulated container and gel packs, ensuring the packs are not frozen solid against the vial.
Consequences of Using Medication Past the BUD
Using compounded tirzepatide after the Beyond Use Date or after improper storage introduces risks related to both the drug’s effectiveness and its safety. One significant concern is the loss of potency, where the active drug molecule slowly degrades over time due to chemical changes. This degradation means the medication will not deliver the full intended dosage, making the treatment less effective for managing diabetes or body weight.
The other major concern involves potential chemical degradation and the risk of microbial growth, especially since the product is an injectable sterile preparation. The breakdown of the tirzepatide molecule can result in the formation of unknown byproducts, which may be harmful or cause an adverse reaction. Additionally, after the BUD, the pharmacy can no longer guarantee the sterility of the preparation, increasing the danger of introducing harmful germs during injection.