When treating oncology patients, technicians realize more stress and job pressure with dealing with chemotherapy drugs that
are vasosclerotics such as Adriamycin™ (doxorubricin). What is a vasosclerotic drug? How harmful are they when extravasated?
What can be done to prevent problems? What can be done to soothe the situation once a spill is identified?
Vasosclerotic drugs create a variable degree of localized tissue injury around the vein resulting from a perivascular leak
or spill. Doxorubricin (Adriamycin®) is the most potent vasosclerotic chemotherapy that this author is aware of. This agent
belongs to the aminoglycoside family and is commonly used in veterinary oncology to treat a variety of malignancies including
lymphoma and adenocarcinomas and soft tissue sarcomas.
Tissue injury can be extensive if the extravasation goes undetected and untreated. Even small amounts of adriamycin can create
severe, irreversible indolent tissue damage. Actinomycin D is also a severe vasosclerotic. Vincristine, vinblastine and mechlorethamine
(Mustargen®) are moderate vasosclerotics. Cis-platin, mitoxantrone, dacarbazine (DTIC), 5-fluorouracil, mithramycin, etoposide,
streptozotocin and bleomycin are considered mild vesicants.
When dealing with chemotherapy agents is important to clearly identify drugs according to their "vasosclerotic" potential.
This author uses chemotherapy treatment forms that have a vasosclerotic warning box that is circled or checked by the doctor
as he/she writes the order. This safety precaution alerts the nursing staff that localized tissue injury will result if there
is a spill.
The nursing staff will notice most perivascular leaks right away. A "bleb" or swelling appears immediately adjacent to the
venipuncture site. Some oncology patients experience immediate discomfort. They squirm or cry or struggle. If the patient
is sedated during the procedure, the nursing staff should have direct supervision during the infusion of the vasosclerotic.
It is important that the nursing staff feels free and obligated to point out loud and clear to the attending doctor when a
leak is suspected. If the patient is sent home with an undetected extravasation, the client may notice a problem within hours
or within 10 days following chemotherapy. The pet starts licking the venipuncture site. The client calls the hospital with
the complaint that the pet has pain, swelling, inflammation, desquamation and/or limping.
Insist on Sedation When Needed for all Vasosclerotics
For their own safety, all cancer patients that resist restraint, during the administration of any caustic chemotherapy agent,
require sedation. As a matter of policy, sedation must be recommended for patient safety to avoid struggling and accidental
extravasation. There should be no exceptions when dealing with adriamycin. Take the time to educate the pet's family by saying
something like this, "Without sedation, your pet may pull away or struggle during the chemotherapy administration. This could
cause some of the drug to spill outside of the vein. The drug may cause severe tissue damage that may ultimately require amputation."
The attending staff must be vigilant in deciding which patients need sedation and which do not. The sedation procedure will
incur more expense but it is for the patient's own good. If your attending doctor is not in agreement with your recommendation
for sedation and your gut feeling about a pet's cooperation, you must speak up and plead for the pet's safety.
When using adriamycin, avoid acepromazine and phenothiazines and drugs that cause arrhythmias or vasodilatation. This author's
R.V.T. staff prefers to use the low dose combination of domitor-butorphanol-atropine (low dose DBA). It is given IV, and reversed
with Antesedan™. We find this combination ideal for most otherwise healthy cancer patients. Many veterinarians prefer to use
Domitor™ strictly on the recommended intramuscular (IM) dose. Telazol® is preferred by some clinicians for immobilization
of healthy fractious dogs.
Animals with heart disease, advanced age, renal failure, hepatic compromise or wasting are at a somewhat higher risk of adverse
events while under sedation. An option that some attending doctors prefer to use is a combination of fentanyl (a short acting
opioid) and midazolam (a short acting benzodiazepine) IV. This combination avoids bradycardia which is commonly found with
domitor. A combination of butorphanol and diazepam IM or IV is another good option for elderly pets that is safe and generally
effective. Some attending doctors feel that the best method is to use a mask, or closed-chamber sedation/anesthesia, with
inhalation anesthesia (sevoflurane/isoflurane). This method is often preferred for geriatric feline cancer patients. The objective
is to immobilize the patient for safety, during administration of caustic vasosclerotic chemotherapy drugs.