Managing complications of chemotherapy (Proceedings)
Apr 01, 2008
CVC IN WASHINGTON, D.C. PROCEEDINGS
Please be aware that these notes are not designed to be a complete reference. It is advisable to consult with an oncologist for current treatment recommendations prior to developing a therapeutic plan for your patient.
Chemotherapy can cause adverse effects in veterinary cancer patients. Because cytotoxic drugs target rapidly dividing cells, normal proliferating cells may be affected. Most commonly affected are the gastrointestinal epithelium, bone marrow, and active hair follicles. In addition, some agents cause unique toxicities. Organ dysfunction or mutations in MDR1 (gene coding for p glycoprotein) affect clearance of chemotherapy drugs and increase the risk of toxicity. It is important for veterinarians to know possible effects, how to prevent morbidity, and how to manage adverse effects. This lecture will focus on managing adverse effects of chemotherapy.
Extravasation is a preventable complication of chemotherapy!
1. Know the toxicities (including potential for extravasation injury) of drugs BEFORE you give them.
2. Proper vein selection
a. Healthy, reasonably sized, accessible, not over joints or tendons
b. Not used for phlebotomy that day
c. No previous extravasation sites
d. Change to another vein if go through vein, vein "blows", no flashback, doesn't flush easily, or if any doubt of placement.
3. Proper administration techniques
a. Only competent technicians and clinicians with training in risk identification, prevention and management of extravasation, IV catheter placement and use of venous devices, and components of adequate documentation should administer IV chemotherapy.
b. Patient comfort essential: need appropriate number of trained restrainers, quiet room, comfortable positioning on mat or blanket, and sedation for fractious or restless patients.
c. Place appropriate IV catheter: use smallest gauge required, long enough that it will not slide out, consider whether a central or peripheral line is needed, consider the duration that the catheter will be in place. Butterfly catheters should not be used for vesicant drugs.
d. Tape catheter securely in a manner that allows visualization of insertion site.
e. Check for flashback and flush with >5 ml of saline (no heparin) to check patency (watch for bleb and palpate vein while flushing).
f. Chemotherapy agents should be diluted appropriately and administered at the proper speed. Some may be given by the "side arm" method.
g. Monitor patient and administration site closely.
h. Record date, site, drug.
i. Have extravasation management plan readily available and memorize initial steps.
Management of extravasation of common chemotherapy drugs
1. Aspirate back as much drug as possible BEFORE PULLING IV catheter. Pull catheter. Aspirate bleb.
2. Apply compress – cold for all drugs except warm for vinca alkaloids 15 min q4hr for 72 hrs.
3. Specific antidotes:
a. Vinca alkaloids: Infuse 1ml of 1% hyaluronidase for each ml of drug extravasated locally into extravasation site to help absorption of drug.
b. Doxorubicin (preliminary information): Treat with dexrazoxane (Zinecard). Canine dosing (Plumb Formulary): Give 3 consecutive IV doses at 24 hr intervals at a dose of 1000 mg/m2 x 2 days, then 500 mg/m2 day 3. Given IV over 15 minutes. Efective if given within 3-6 hours of extravasation.
One report in a cat: Single dose at 10X doxorubicin dose IV.
Possible side effects: Myelosuppression. Expensive.
Apply 90% DMSO topically to site q 6-8 hrs for 14 days. No occlusive dressings and WEAR GLOVES!
Role of resection of extravasated drug?
Other: E collar, surgical debridement if ulcer forms, antibiotics if open lesion.