A single-dose vial (SDV) is a container of sterile medication intended for parenteral administration, meaning it is meant for injection or infusion. The definitive answer to whether this type of vial can be used more than once is no. Patient safety protocols mandate that an SDV must be used for a single patient, one time only, and then immediately discarded. This strict rule exists to prevent life-threatening infections, which can occur when the sterility of the injectable medication is compromised.
The Difference Between Single-Dose and Multi-Dose Vials
The distinction between a single-dose vial and a multi-dose vial (MDV) is based primarily on their chemical formulation and intended duration of use. Single-dose vials are designed to be preservative-free or contain only trace amounts of antimicrobial agents. This formulation is often preferred for sensitive patients, but it simultaneously leaves the medication unprotected once the container is accessed.
In contrast, multi-dose vials contain an antimicrobial preservative, such as benzyl alcohol, which is added to inhibit the growth of bacteria introduced during repeated access. This preservative allows the MDV to be used multiple times for the same patient over a limited period, typically up to 28 days after the first puncture, unless the manufacturer specifies a different date. The presence of this bacteriostatic agent provides a chemical defense against microbial contamination that the SDV completely lacks.
The volume of medication in an SDV can sometimes be more than what is required for a single treatment, which can create a temptation to save the remaining drug. However, the designation as “single-dose” is based on the lack of preservatives and the container’s design, not solely on the volume of the contents. The manufacturer labels the container based on its chemical properties and safety profile, making the label the determinant of proper usage.
The Primary Safety Concern: Microbial Contamination Risks
Reusing a single-dose vial directly compromises patient safety because the vial’s contents can quickly become a breeding ground for microorganisms. Once the rubber stopper, known as the septum, is punctured by a needle, the sterile seal is broken, and a pathway for contamination is created. Microbes from the ambient air, the technician’s skin flora, or the external surface of the vial can be inadvertently introduced into the liquid medication.
Since single-dose vials lack antimicrobial preservatives, any bacteria or fungi that enter the solution can rapidly multiply without resistance. Medications that contain lipids or sugars, such as the anesthetic propofol, are particularly susceptible because they provide an ideal nutrient source for microbial growth. This process can turn the injectable drug into a contaminated solution within a short time.
The consequences of injecting a contaminated solution can be severe, including localized infections, abscesses, and systemic illnesses such as sepsis. Outbreaks of serious infections, including bloodborne pathogens like Hepatitis B and C, have been directly linked to the misuse of single-dose vials. The contamination is often invisible, meaning the medication can look perfectly clear while containing dangerous levels of infectious agents.
Regulatory Directives and Safe Injection Practices
Health organizations worldwide, including the U.S. Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA), have issued clear, consistent directives against the reuse of single-dose vials. These directives are part of foundational guidance on safe injection practices that all healthcare providers must follow. The underlying principle is to protect patients from the documented risks of infection outbreaks that result from vial misuse.
The absolute rule is that a single-dose vial is for one patient only, for one procedure or treatment session. Once the required dose is drawn, the remaining medication and the entire vial must be discarded immediately. This is necessary even if a substantial amount of medication is still visible inside the container, as the sterility of the remaining contents cannot be guaranteed once accessed.
Proper procedure requires the healthcare provider to draw the dose using aseptic technique in a designated clean medication preparation area. If the vial is punctured but the dose is not immediately administered, the risk of contamination increases, and the vial must still be discarded. To ensure compliance, vials that have been accessed should never be returned to storage on a medication cart or shelf.
Actionable steps for disposal include placing the vial into a designated sharps container or other appropriate waste receptacle immediately after the procedure is finished. This immediate disposal prevents the vial from being mistakenly used for a second patient or saved for later use on the same patient. These official guidelines serve as the final procedural justification for the “one and only one use” rule, prioritizing patient safety over concerns about drug waste.