Dating an opened multidose vial

The expiration date printed for an unopened product does not automatically tell staff how long the vial may be used after first entry. Opening or puncturing a multidose vial creates an in-use period. Dating the vial makes that clock visible and helps prevent use beyond the supported period.

The general 28-day rule

CDC infection-control guidance says multidose vials should be discarded 28 days after opening or puncture unless the manufacturer specifies a different date for the opened vial. This is a general rule for the opened vial—not an automatic extension of the manufacturer’s expiration date. If the manufacturer’s instructions require earlier discard, follow the shorter period.

Mark the first-entry date

When the vial is first entered, write the date of first use and any required beyond-use or discard date according to pharmacy procedure. If the vial arrives with a shorter manufacturer in-use period, use that date. Clear, legible labels help every staff member know whether the vial may still be used.

Storage and access practices still matter

A dated vial is not automatically safe to use. Store it according to the label, inspect it for visible contamination or damage, use a new sterile needle and syringe for each entry, and follow the required clean medication-preparation area practices. If a vial enters an immediate patient-care area, CDC guidance generally calls for dedicating it to a single patient and discarding it after use, subject to applicable policy.

Do not confuse three different dates

• Manufacturer expiration date: applies to the product under labeled storage conditions.
• In-use date: marks when the vial was first entered or opened.
• Beyond-use/discard date: the last date the opened vial may be used under the applicable instructions.

Quick check before use

1. Read the product’s manufacturer instructions and printed expiration date.
2. Check the first-entry date and calculated discard date.
3. Apply the shorter applicable manufacturer or policy limit.
4. Confirm proper storage, vial integrity, and aseptic access practices.
5. Discard a vial with missing or uncertain dating rather than guessing.

For the exam, remember to date a multidose vial when first entered and apply the 28-day CDC guidance unless the manufacturer specifies another opened-vial date. The printed shelf-life date, in-use date, and discard date are related but not interchangeable.