How long can you keep a multidose vial? Understanding the 28-day rule and more

October 12, 2025 •

5 min read

According to the CDC, improper injection practices and handling of multidose vials have been linked to outbreaks of infections, emphasizing the critical importance of knowing precisely how long can you keep a multidose vial after its initial use. This standard practice helps prevent microbial contamination and ensures the medication's integrity and safety for repeated doses.

Quick Summary

The general rule for multidose vials is to discard them 28 days after first access, though manufacturers may specify shorter or longer times. Proper labeling, strict aseptic technique, and correct storage are essential to prevent contamination and ensure medication efficacy. Special exceptions exist for certain vaccines and other specific products based on manufacturer instructions.

Key Points

The 28-Day Rule: The standard beyond-use date (BUD) for most opened multidose vials is 28 days, after which they must be discarded to prevent contamination.
Check Manufacturer Instructions: The 28-day rule is not absolute; always check the manufacturer's package insert, as some products may specify a different, either shorter or longer, duration.
Vaccine Exemptions: The CDC notes that many vaccines are exempt from the 28-day rule, with their BUD tied to the manufacturer's expiration date, but specific vaccine guidelines must be followed.
Aseptic Technique is Vital: Consistent use of aseptic technique, including hand hygiene and using a new, sterile needle and syringe for every access, is the primary method for preventing vial contamination.
Labeling is a Requirement: Opened multidose vials must be immediately labeled with the beyond-use date and the opener's initials to ensure proper tracking and disposal.
Storage Matters: Vials must be stored according to manufacturer specifications (e.g., refrigeration) to maintain the medication's integrity throughout its safe lifespan.
Discard if Compromised: Any vial where sterility is questionable due to improper handling, storage, or damage must be discarded immediately, regardless of the BUD.

Understanding Multidose Vials

A multidose vial is a container of sterile liquid medication that is approved for repeated use, designed to hold more than one dose. These vials are typically equipped with an antimicrobial preservative to inhibit the growth of bacteria that may be introduced during a puncture of the rubber stopper. This preservative, however, does not protect against viral contamination and can lose its effectiveness over time, making diligent handling essential. In contrast, single-dose vials lack this preservative and must be discarded after a single use, regardless of remaining contents. The Centers for Disease Control and Prevention (CDC) and other governing bodies have established stringent guidelines to ensure the safety of patients receiving medication from these vials.

The General 28-Day Rule

The most widely recognized guideline for multidose vials is the 28-day beyond-use date (BUD). Once a vial has been punctured with a needle for the first time, its sterility is considered compromised, and a clock begins. The contents should be discarded 28 days after this initial access, even if the manufacturer's original expiration date is further out. This date is assigned to the opened product to reflect the last date it can be safely used. To adhere to this rule, the vial must be properly labeled with the specific beyond-use date immediately upon initial use. Failure to do so renders the vial unusable, and it must be discarded immediately.

Important Exceptions to the 28-Day Rule

While the 28-day rule is a common standard, it is not universal and has several crucial exceptions. Always consult the manufacturer's specific instructions, as these supersede general guidelines. Some exceptions include:

Manufacturer-Specified Dates: Manufacturers can extend or shorten the dating if they have conducted specific testing to support it. It is not uncommon for a manufacturer to specify a different beyond-use date that is either shorter or longer than 28 days for a particular product.
Vaccines: Many vaccines are explicitly exempt from the 28-day rule. The CDC states that for most vaccines, opened multidose vials can be used up to the manufacturer’s expiration date, provided proper storage and handling have been maintained. For example, the inactivated polio vaccine (IPV) is valid until the manufacturer's expiration date. However, some flu vaccines may have a 28-day discard date, so it is vital to check the product information each season.
Insulin Vials: Insulin, while a multidose product, often has a different beyond-use date. Many insulin products specify a 28-day expiry after opening, but some may have longer or shorter timeframes. A study published in the Journal of Small Animal Practice even suggested that refrigerated multi-dose insulin vials could remain sterile for longer, but this doesn't override the standard clinical guidelines.
Compromised Sterility: Any time the sterility of the vial is compromised or even questionable, it must be discarded immediately. This includes accidental contamination, improper storage, or the vial entering an immediate patient care area for multi-patient use.

Key Factors Affecting Vial Longevity

Beyond the date itself, several factors influence the safety and longevity of a multidose vial once it has been accessed:

Aseptic Technique: Using proper aseptic technique with every access is the most important defense against contamination. This involves hand hygiene, disinfecting the vial stopper with 70% alcohol and allowing it to dry, and using a new, sterile needle and syringe for each dose.
Storage Conditions: Improper storage, such as exposure to extreme temperatures or direct sunlight, can compromise the medication's stability and efficacy. Vials must be returned to their appropriate storage temperatures between uses.
Single-Patient Use: Dedicating multidose vials to a single patient whenever possible is the safest practice. This eliminates the risk of cross-contamination between patients, which is a major concern in healthcare settings. If a vial must be used for multiple patients, it should be restricted to a centralized medication preparation area and never enter an immediate patient treatment space.
Physical Integrity: The physical condition of the vial is also important. If the rubber stopper is repeatedly punctured, it can leak, increasing the risk of contamination. Some protocols limit the number of punctures to 20 per vial.

Safe Handling and Labeling Practices

Properly managing multidose vials requires consistent, disciplined practice. Key steps include:

Preparation Area: Always prepare medication in a dedicated clean area, away from patient treatment zones.
Hand Hygiene: Perform hand hygiene before handling the vial.
Inspection: Visually inspect the vial for damage, particulates, or discoloration. Do not use if any are present.
Labeling: The moment a multidose vial is accessed, it must be labeled with the beyond-use date. This is the calculated discard date, not just the date it was opened. Including the initials of the person who opened it is best practice.
Aseptic Access: Clean the vial's rubber stopper with an alcohol swab using friction, and let it dry completely before inserting a new, sterile needle. Never reuse a syringe or needle, even for the same patient.
Storage: Adhere to the manufacturer's storage instructions and ensure the vial is returned to the correct temperature after use.
Disposal: Discard the vial immediately if the beyond-use date is reached, sterility is compromised, or the vial is damaged. Do not 'pool' leftover contents from multiple vials.

Comparison of Expiration Date vs. Beyond-Use Date


Feature	Manufacturer's Expiration Date	Beyond-Use Date (BUD)
Definition	The last date a manufacturer guarantees the unopened medication's full potency and safety if stored correctly.	The last date an opened or repackaged medication can be used, ensuring safety and potency.
Application	Applies to an unopened vial.	Applies to a vial after its first puncture.
Assigned By	The manufacturer, based on extensive stability testing.	The healthcare provider or patient, based on best-practice guidelines and manufacturer instructions.
Rule of Thumb	The BUD can never be after the manufacturer's original expiration date.	The BUD is typically 28 days after first puncture unless a different timeframe is specified.

Conclusion: Prioritizing Patient Safety

Ultimately, the question of how long can you keep a multidose vial is a matter of strict patient safety protocol. While the general rule is 28 days after first puncture, this is subject to manufacturer guidelines and the specific type of medication. The presence of preservatives does not negate the need for rigorous aseptic technique, proper labeling, and adherence to storage conditions. Healthcare professionals and patients alike must remain vigilant to prevent contamination risks and ensure the efficacy of injected medications. Following standardized procedures, always checking manufacturer labeling, and defaulting to the most conservative discard date are the safest and most responsible practices. For more in-depth information, the CDC provides detailed clinical guidelines on safe injection practices.(https://www.cdc.gov/injection-safety/hcp/clinical-safety/index.html)

Frequently Asked Questions

The expiration date is set by the manufacturer and applies to an unopened vial. The beyond-use date (BUD) is determined by the clinician or patient after the vial has been opened or punctured, indicating the period during which it can be safely used, which can never exceed the manufacturer's expiration date.

No, the 28-day rule is a general guideline. Many exceptions exist, most notably for certain vaccines which can often be used until the manufacturer's expiration date, provided they are handled and stored correctly.

For patient safety, multidose vials should be dedicated to a single patient whenever possible. If used for multiple patients in a clinical setting, they must be restricted to a clean, centralized medication preparation area and never enter an immediate patient treatment space.

If an opened vial does not have the proper beyond-use date label, its sterility and safety cannot be guaranteed. It must be discarded immediately to prevent the risk of contamination.

No, you should never 'pool' or combine leftover partial doses from multiple vials. This practice increases the risk of contamination and compromises medication integrity.

Expired or contaminated vials should be disposed of in the proper manner, often by returning them through a drug collection program or following local regulations for safe pharmaceutical waste disposal.

No, a new, sterile needle and syringe must be used for every access of the vial, even for the same patient. Reusing injection equipment, even if the needle is changed, can lead to serious infections.