Why are Drug Expiration Dates Important to Your Veterinary Practices and Patients?

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The Main Takeaways:

  • Expiration dates, which are used by 503B manufacturers offer benefits to veterinary patient care that beyond-use dates do not.
  • Using medications that have expiration dates can maximize veterinary practice profits by reducing expenses.
  • Medications from 503A pharmacies with BUDs have small usage windows – as little as 12 hours for sterile products!
  • 503B manufactured products have a shelf-life range of months to years, without compromising quality.

In veterinary medicine, dates matter—specifically drug expiration dates. The testing that goes into determining accurate expiration dates enables veterinarians to be assured they are providing safe and effective medication to their patients. Plus, when compounded drugs, specially formulated to meet the unique needs of veterinary patients, go through the testing required to be labeled with an expiration date, it allows veterinary hospitals and clinics to keep these drugs in stock for office use— improving patient care, while minimizing costs. The ability to have standing orders also optimizes inventory management and budgets by reducing unit prices.

What is a drug expiration date?

An expiration date indicates how long a drug is expected to maintain its stability, meaning its strength, purity, and quality when the drug is stored in accordance with the conditions specified on its label. Expiration dates are determined based on the results of rigorous stability testing that meets Food and Drug Administration (FDA) standards.

Most commonly, expiration dates are found on commercial pharmaceutical products. However, 503B outsourcing facilities, which manufacture large batches of drug products for office use, are held to the same FDA manufacturing standards as large pharmaceutical companies. This means 503B’s are required to label their products with expiration dates, giving veterinary professionals an advantage in patient care.

Are expiration dates and beyond-use dates (BUDs) the same thing?

Expiration dates and BUDs are similar in that they both are indicators of a drug’s shelf-life, but they are not exactly the same. Expiration dates can only be assigned to a drug after extensive testing is completed.

In contrast, BUDs are assigned to medications that have been prepared by traditional 503A compounding pharmacies for individual patient use. By United States Pharmacopeia (USP) definition, BUDs are “the date or time after which a compounded sterile preparation shall not be administered, stored, or transported” (USP <797>) and for nonsterile compounded drugs as “the date after which a compounded preparation should not be used; determined from the date the preparation is compounded” (USP <795>).  The key difference that impacts veterinary patients – 503As aren’t required to put their medications through stability testing. Our previous blog took a deeper dive into the differences between BUDs and Expiration dates.

Expiration dates and beyond-use dates sound interchangeable, but they have key differences.
Download our 1–pager for a quick reference guide on the differences in the safety and quality of the products you administer to your patients.

What are the benefits of stocking manufactured products with an expiration date rather than a compounded preparation with a beyond-use date?

There are two main benefits to choosing manufactured drugs with an expiration date instead of those with a beyond-use date—minimizing veterinary hospital or clinic expenses and improving patient care.

Improved Practice Budget – Bottom Line Benefits of Expiration Dates

Traditionally, many veterinary hospitals and clinics utilized neighborhood or online 503A compounding pharmacies to fill prescriptions for compounded medications. The USP sets the standards for BUDs on these preparations and the timeframe is typically quite short, limiting nonsterile compounded medications beyond-use dates to a range of 14 days to a maximum of 6 months. The BUD could be even sooner based on the earliest expiration date of any ingredient used. Table 1 explains more.

Table 1

Beyond-Use Dates for Compounded Nonsterile Preparations From 503A Pharmacies

Formulation Type

Beyond-Use Date*

Water-containing oral formulations

14 days (max)

Water-containing topical/dermal and mucosal liquid and semisolid formulations

30 days (max)

Nonaqueous formulations

6 months (max)

*The beyond-use date may be sooner based on the earliest expiration date of any ingredient used.

From “USP Compounding Standards and Beyond-Use Dates” by United States Pharmacopeia, 2019 (https://www.usp.org/sites/default/files/usp/document/our-work/compounding/usp-bud-factsheet.pdf).  

For sterile preparations compounded in a 503A pharmacy, BUDs are restricted to as little as 12 hours up to a maximum of 45 days (see Table 2). USP guidelines allow for BUDs to be extended if the 503A pharmacy can provide stability and sterility testing data to support an extension; however, this testing isn’t a typical practice in most 503A pharmacies due to lack of resources.

Table 2

Beyond-Use Dates for Compounded Sterile Preparations From 503A Pharmacies

Microbial Contamination Risk Level

Beyond-Use Date

Low-risk in segregated compounding area

·       12 hours at CRT*


·       48 hours at CRT

·       14 days refrigerated

·       45 days frozen


·       30 hours at CRT

·       9 days refrigerated

·       45 days frozen


·       24 hours at CRT

·       3 days refrigerated

·       45 days frozen

*Controlled room temperature (CRT)

From “USP Compounding Standards and Beyond-Use Dates” by United States Pharmacopeia, 2019 [PDF] 

In contrast to the BUDs assigned to compounded drugs from 503A pharmacies, the expiration dates assigned to 503B-manufactured products can range from months to years.

The longer timeframe associated with expiration dating makes it practical to keep 503B-manufactured products stocked for office use, allowing patients to receive immediate care while also maximizing practice profitability by:

  • Minimizing expired drug waste. After labor costs, inventory is the next largest expense incurred by veterinary practices, so waste resulting from outdated, unusable drugs must be minimized to avoid unnecessary gross revenue consumption.
  • Reducing the costs associated with tracking, storing, and properly disposing of outdated drugs. Managing expired drugs utilizes costly labor hours, while keeping expired drugs in a quarantined storage area consumes valuable real estate.
  • Reducing new customer acquisition costs. Being able to provide clients with high-quality, tested manufactured drugs in addition to quality care provides veterinary hospitals and clinics with another touchpoint to increase client loyalty and reduce expenses associated with replacing lost clientele.

Improved Patient Care

The expiration dates assigned to 503B manufactured products are determined through extensive stability testing that is required and dictated by the FDA’s cGMP regulations. 503A compounding pharmacies do not typically have a thorough stability program in place and develop BUDs using clinical literature and USP guidelines instead of direct data and evidence, making BUDs less reliable than expiration dates.

Because pharmaceutical drug products can potentially undergo changes in chemical composition and release potentially harmful byproducts over time, stability testing is crucial to determining how long a medication can be stored and remain safe and effective for patient use. The robust testing programs in place at a 503B incorporate analysis of several different types of stability for each product line produced including:

  1. Chemical: Does every active ingredient maintain its indicated potency and chemical integrity within a set tolerance range?
  2. Microbiological: Is drug sterility, if applicable, maintained in alignment with acceptable limits? If antimicrobial agents were incorporated into the drug, are they maintaining their effectiveness?
  3. Physical: Are palatability (both taste and smell), appearance, particle size, solubility, and viscosity of the drug maintained?
  4. Therapeutic: Does the drug retain its therapeutic effectiveness?
  5. Toxicological: Is there a significant rise in drug toxicity?
The assessment of each of these drug qualities by a 503B means:
  • The product strength stated on the drug’s label is accurate, so patients are receiving medications that will deliver the treatment needed to support effective care. Under most circumstances, 90% of the labeled potency is considered the lowest limit for acceptable potency level.
  • Drug dosage is consistent from batch to batch. The range of dose that is appropriate for veterinary patients is quite small, so dosage consistency is an important issue in veterinary medicine, and is especially critical in certain areas like oncology care where underdosing means that cancerous cells are likely going to become resistant to drug treatment and overdosing puts the patient at significant risk of harm from drug toxicity.  
  • There’s a higher likelihood that patients will accept treatment because drug palatability is retained. As a result, it is also more likely that clients will adhere to the treatment schedule.
  • Exposure to contaminated drugs and toxic byproducts are significantly reduced, maximizing patient safety.
  • Your practice can keep frequently used drug products stocked for on-demand prescribing or administration, allowing patients to receive immediate, high-quality treatment. Additionally, direct counseling can be given to clients from knowledgeable veterinary staff on appropriate drug administration and side effects that may occur. 

Purchasing veterinary drugs with longer timeframes for useability from a 503B outsourcing facility can be a useful component of an inventory management strategy that increases profitability by reducing practice costs associated with drug waste while providing improved patient care.

If you still have questions about stability testing, our team is happy to answer questions and help you determine the best options for your in-office stock and your individual patients. Contact our team.

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