Multidose Chemo Vials

By Marc Stranz, PharmD, RPh

Ask the Pharmacist...

Q: An issue has recently arisen in our Oncology office regarding the storage and handling of chemotherapy drugs when only part of a vial has been used for a given dose. We (RN/MD staff) mix our drugs in a hood and do not have a pharmacy. I am hoping some of the pharmacists on the list might be able to clarify matters, or steer me to a good reference.

I use the drug insert from the manufacturer as my guide and try to follow what it says in terms of saving unused drugs for use on another patient. Some give very clear and specific instructions about whether unused drug can be saved, or if it needs to be discarded. However, a number of the inserts just address storage of unopened vials (which is until the expiration date) and stability of drugs that have been diluted as recommended. Others, such as Onxol, don’t specifically state whether a partially used vial can be used again or not. There are several drugs (5FU comes to mind) that describe the vials as "Multidose Vials" but say to "discard unused portion", which sounds completely contradictory to me, unless MDV means something different in pharmaceutical terms.

We don’t have a copy of Trissel’s in the office but if that is a reliable reference that would hold up if a legal issue should ever arise, we could purchase one. There really are two issues here, stability and sterility, and I am baffled by the lack of consistency in labeling on the part of the manufacturers.

A: As a policy, manufacturers state to discard most "accessed" drug containers proximate to initial use. It is not a question of drug stability in almost all cases (but there are a very few drugs impacted by exposure to air). The manufacturer bases their precautions on the potential of infectious contamination or improper storage, as they cannot control the environment and method under which the product is accessed or stored.

There are trials showing minimal vial contamination even under relatively uncontrolled circumstances (e.g., insulin in a patient's refrigerator). There are data in Trissel's on drug stability in the vial after reconstitution of drug powder. There is little or no information on what could happen to a partially used vial of drug that came in a "ready-to-use" form.

If you want to be scientific, you could put some agar into the partial vials and see if anything grows after 14 days. Keep the vials at room temperature. I doubt you'll discover anything, but it shows you documented the validity of your accessing and storage process.

Most pharmacies access the vials under aseptic conditions, after alcohol sterilization. Ideally, it is handled through gloves sterilized by alcohol and the vial is protected from the operator with masks, etc. After accessing, they clean it with alcohol again and cover the port with an aluminum foil seal. It is then dated and initialed by the operator, and stored in the refrigerator (unless contraindicated by the drug type) until the next use, it reaches its expiration date (from Trissel's), or personal judgment that they don't want to use it.