Know When and How to Address Med Overfill

  We're getting questions about overfill of injectable meds.

  This extra liquid is meant to ensure ordered volumes can be given. But it may cause confusion, errors, and other problems.

  Know when and how to address overfill.

  IV bags or bottles. Be aware that diluents (D5W, normal saline, etc) have around 10% overfill.

  Follow pharmacy policies for handling diluent overfill...to optimize dose accuracy, med stability, etc.

  For instance, you usually won't need to consider overfill with antibiotics. Exact concentration isn't likely to be critical...and the whole bag will be infused, so patients get full doses.

  But exact volume and concentration are important for some meds, such as certain chemo or if specified in product labeling. In this case, transfer a specific diluent volume into an EMPTY container.

  Vials or ampules. Anticipate that these will often have a small amount of overfill.

  Don't draw up the extra when using one whole med vial or amp to prep a dose. Instead, draw up the actual volume you need.

  For instance, drawing up all the solution from a tobramycin 80 mg/2 mL vial might give you a dose that's closer to 90 mg.

  Keep in mind, using overfill can be beneficial in other cases...for cost savings, maximizing supplies during shortages, etc.

  For example, extra full doses can be drawn up from some COVID-19 vaccine vials.

  Syringes. Add overfill when prepping certain doses in syringes...such as some that are 1 mL or less dispensed with a cap instead of a needle...according to pharmacy policies.

  This makes up for volume lost when a nurse attaches a needle and injects the med. Some solution will remain in the "dead space" of the needle hub after administration.

  Clearly label these syringes to indicate there's overfill...so nurses know to give just the ordered volume.

  Get our resources, Sterile Compounding: Keeping It Clean and Injectable Meds: Beyond Sterile Prep, for more med prep and dispensing tips.

Key References

  • https://www.raps.org/regulatory-focus%e2%84%a2/news-articles/2015/6/fda-finalizes-guidance-on-overfilling-injectable-vials (5-3-22)
  • https://www.ismp.org/resources/understanding-and-managing-iv-container-overfill (5-3-22)
  • https://www.ismp.org/guidelines/sterile-compounding (5-3-22)
Hospital Pharmacy Technician's Letter. May 2022, No. 380525



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