Chemotherapy Safety for the Veterinary Patient and Personnel
Esther Chon, DVM, DACVIM (Oncology)
echon@mvsvets.com
Chemotherapy – also known as antineoplastic or cytotoxic drugs – include any drug
that inhibits or prevents the function of cells. These drugs are considered hazardous drugs
according to the National Institute for Occupational Safety and Health (NIOSH) because
they are known or suspected to cause adverse health effects from exposure in the
workplace. For most chemotherapy drugs, the actions are not specific to tumor cells.
Therefore, exposure of patients and others to these drugs can produce unwanted and
dangerous effects. The utmost care must be used to prevent accidental exposure to both
the veterinary patient and anyone handling the hazardous drug or its metabolites.
Safe Chemotherapy Administration for Veterinary Patients
As with any drug, chemotherapy drugs should be administered appropriately to
each patient. More specifically, the correct drug, correct dose, and correct route of the
drug should be administered to the correct patient (the 4 C’s). When chemotherapy
drugs are administered via the parenteral route, the patient should be restrained in such a
way that the drug can be given safely in only the intended route (e.g. without risk of
extravasation for intravenous drugs). This will require at least one person to hold the
patient, another person to administer the drug, and may involve the need for sedation.
For intravenous drugs, a secure intravenous catheter should be placed. Butterfly
catheters should not be used because of the risk of extravasation and potential
unintentional exposure to the patient’s other body parts or to the personnel. The
intravenous catheter should be placed after one clean stick, secured with tape, and flushed
amply with saline to ensure there are no leaks. In addition to ensuring the correct drug,
dose, route, and patient, the correct administration rate (the 5th C) should also be certain
before administration is initiated. Any parenteral chemotherapy administration should be
done on an absorbent pad. Check intermittently for a flashback during the infusion. Flush
thoroughly with saline after completion of the infusion, and apply gauze over the injection
site when removing the catheter to prevent spatter of chemotherapy-containing blood. All
materials used, including the absorbent pad, should be placed in a biohazard bag.
All calculated and drawn up/counted doses should be checked by at least one other
person.
I personally use the following triple-check system:
- I calculate the drug dose and write it on a chemotherapy prescription sheet.
- My oncology technician checks the calculated dose and indicates that she has checked the dose (first check).
- My oncology technician draws up/counts the drug.
- I check that the correct drug and volume has been drawn up/counted, and I indicate that I have checked these on the prescription sheet (second check).
- My oncology technician checks the 5 C’s before administering the drug (third check).
- The chemotherapy drug should be administered in a no-traffic area. The room should be quiet and have no interruptions. I personally have a closed door (with closed shades to the window on the door) in an oncology-treatment-specific room. There is a sign on the door prohibiting entry or knocking. Sedation is used if necessary.
Extravasion injury can happen despite taking every precaution. Fortunately, the
incidence is extremely low, but one should be aware of the signs of an extravasation as
early as possible. The initial signs are the absence of blood return from the catheter,
resistance to flushing, and patient discomfort/pain on administration. Later signs include
swelling or redness around the extravasation site that can eventually lead to tissue
ulceration, blistering, and possibly tissue necrosis. Different drugs require different
management strategies post-extravasation. Vesicants such as doxorubicin should be
localized and neutralized with dry cold compresses and administered its antidote
(dexrazoxane) within the first 2 hours of extravasation. Vesicants such as the vinca
alkaloids should be dispersed and diluted with dry warm compresses and administered
hyaluronidase injections if available.
For oral chemotherapy drugs, if a pill popper is required, the pill popper is saved for
the specific patient for repeated administrations. The same pill popper is not used between
different patients to prevent cross contamination. Similarly, the pill counter trays are
designated for a specific drug (such as chlorambucil, lomustine, etc). Pill poppers are kept
in a biosafety bag and stored inside the biosafety cabinet along with the pill counter trays.
Chemotherapy Safety for Veterinary Personnel
Hazardous drugs have the potential to be teratogenic, carcinogenic, and/or
mutagenic. Since it is difficult to determine the true acceptable level of risk of
chemotherapy to a specific individual, every precaution should be taken to minimize
exposure to as low as reasonably achievable to anyone handling a hazardous drug or its
metabolites. I encourage any veterinarian who uses hazardous drugs (in addition to
chemotherapy) in their hospital to read the listed references at the end of this section for
detailed information on the safe handling of these drugs.
Care should be taken at every phase of contact, which begins with chemotherapy
receipt. Contamination has been documented on intact vials that are received directly from
the manufacturer. Chemotherapy should be stored in designated low-traffic areas and
reconstituted/mixed/prepared in a biosafety cabinet (hood). Any chemotherapy spills
should be handled with a chemotherapy-specific spill kit. Chemotherapy should be
administered in a designated area for chemotherapy only. Treated patients should be
handled appropriately, as they become a source of contamination. Any patient waste postchemotherapy
treatment should be handled with chemotherapy gloves and disposed of in a
biohazard bag. Any treatment area should be cleaned with a chemotherapy-neutralizing
product. Personal protective equipment (PPE) – which includes an impermeable gown,
chemotherapy-approved gloves, lint-free minimum N95 respirator, a full face shield, and
goggles – should be worn at every phase of chemotherapy contact.
PPE is the last line of defense against hazardous drugs and represents the lowest
effective level of protection. For the safe handling of chemotherapy, additional physical
changes to the work area and process should be made to enclose, isolate, or redirect the
hazardous drug. Such changes include the use of a ventilated cabinet (biosafety hood),
closed-system transfer device, and dedicated and separate areas for chemotherapy drug
preparation, administration, and patient care.
There are many types of ventilated hoods available. My preference is a Class II, type
B2 hood that has vertical laminar flow, positive pressure with air drawn in via HEPA
filtration, and 100% exhausted air to the outside via HEPA filtration (no re-circulation of
air). I also utilize a closed-system transfer device that mechanically prevents the escape of
hazardous drugs out of the system and prevents environmental contamination into the
system. Chemotherapy is prepared in a designated room in which the biosafety cabinet is
housed and where the chemotherapy drugs are stored. Refrigerated chemotherapy drugs
are stored separate from any other refrigerated drugs or food. Chemotherapy is
administered in a separate chemotherapy treatment area. Patients who have received
chemotherapy are labeled as such in a designated ward. Any wastes from patients that
have received chemotherapy are handled with chemotherapy gloves, and soiled
chemotherapy patient laundry is washed separately from other laundry. If there is risk of
splashing, full PPE is worn. Finally, clients are advised to use nitrile gloves when handling
excreta of their pets for 72 hours after they have received chemotherapy, with the
precaution to walk their dogs in low-traffic areas to prevent exposure to other animals and
people.
In December 2019, the USP 800 is scheduled to regulate the way we handle
hazardous drugs, although the exact mechanism by which regulation is executed has not
yet been determined. Because the best safety strategy is to eliminate the hazard, the
appropriate management of veterinary cancer patients may entail referral of the patient to
a practice that is equipped to handle and manage the use of hazardous drugs.
References
USP General Chapter <800> Hazardous Drugs-Handling in Healthcare Settings, From
USP 40-NF 35, Second Supplement (2017), www.usp.org
NIOSH Hazardous Drug Exposures in Healthcare, www.cdc.gov/niosh/topics/hazdrug/
ACVIM small animal consensus statement on safe use of cytotoxic chemotherapeutics in
veterinary practice. Smith AN et al. J Vet Intern Med, 2018;32(3):904-913.
Engineering controls in veterinary oncology: A survey of 148 ACVIM board-certified
oncologists and environmental surveillance in 20 specialty hospitals. Alexander K et al.
Vet Comp Oncol, 2018;16(3):385-391.
Chemotherapy safety in clinical veterinary oncology. Klahn S. Vet Clin North Am Small
Anim Pract 2014;44(5):941-62.
2016 AAHA Oncology Guidelines for Dogs and Cats. Biller B et al. J Am Anim Hosp Assoc
2016;52(4):181-204.
144 2019 Emerald Coast Veterinary Conference
