DM3 Pt8-2 Safe Chemotherapy Flashcards
What are the three biggest potential risks associated with chemotherapy in cats?
- Bone marrow suppression 2. Gastrointestinal toxicity 3. Extravasation.
What are some less common side effects of chemotherapy in cats?
Anaphylaxis, hepatotoxicity, and nephrotoxicity.
What oncological emergency can result from a successful tumor kill in cats with lymphoproliferative disease?
Tumor lysis syndrome.
What oncological emergency can result from chemotherapy in gastrointestinal lymphoma?
Gastrointestinal perforation and peritonitis.
Which chemotherapeutic agents are commonly used in the treatment of lymphoma in cats?
Cyclophosphamide, chlorambucil, vincristine, and doxorubicin.
What are some side effects associated with specific chemotherapeutic agents like L-asparaginase and hydroxyurea?
L-asparaginase can cause anaphylaxis, while hydroxyurea can cause gastrointestinal and bone marrow toxicity.
What is the key to the successful use of chemotherapeutic agents in cats?
Prevention and early detection of potential complications to avoid oncological emergencies.
How can the risk of oncological emergencies from chemotherapy be reduced in cats?
By predicting side effects, preventing them, and managing them early before serious clinical consequences arise.
Why is bone marrow suppression a risk with chemotherapy in cats?
Chemotherapeutic agents affect rapidly dividing cells, including those in the bone marrow.
Which chemotherapeutic agent is more myelosuppressive: cyclophosphamide or vincristine?
Cyclophosphamide is more myelosuppressive than vincristine.
What is the most common consequence of bone marrow suppression in cats?
Neutropenia, due to the short half-life of neutrophils (7-8 days).
What is the time frame for neutrophil nadir after chemotherapy in cats?
5-7 days after drug administration.
What are the main concerns with severe myelosuppression if undetected?
Severe myelosuppression can lead to sepsis.
How should a cat with neutrophils < 1.5x10⁹/l but clinically well be managed?
Give broad-spectrum oral antibiotics for 5-7 days and have the owner monitor the cat at home.
What should be done if a cat is systemically ill or pyrexic due to myelosuppression?
The cat should receive aggressive treatment with intravenous antibiotics and supportive care. The dose of the next chemotherapeutic treatment should be reduced by 20%.
What is a key preventive measure for managing bone marrow suppression in cats?
A complete blood count (CBC) should be performed before each chemotherapy dose to check neutrophil and platelet counts.
How can dose accuracy be ensured for chemotherapeutic agents?
The cat should be weighed at each visit, and doses should be calculated based on body surface area.
What should owners monitor for after their cat receives chemotherapy?
Any signs of illness, especially around the time of the neutrophil nadir (5-7 days after treatment). If illness occurs, a CBC should be performed.
What are common gastrointestinal (GI) side effects of chemotherapy in cats?
Anorexia, nausea, vomiting, and diarrhoea.
Which chemotherapeutic drug is most commonly associated with anorexia in cats?
Doxorubicin, likely due to nausea.
What side effect is associated with vincristine in some cats?
Paralytic ileus, a rare side effect, which can occur after vincristine administration.
What should be done if gastrointestinal signs occur with vincristine?
Care should be taken in using it again, as clinical signs may worsen with continued use.
What are the potential causes of gastrointestinal signs in cats undergoing chemotherapy?
Chemotherapeutic drugs, concurrent disease, progression of neoplasia, or GI perforation (especially in GI lymphoma).
What medications can be used to manage chemotherapy-induced nausea and vomiting in cats?
Antiemetics like maropitant and metoclopramide.
What supportive treatments can be used for cats with chemotherapy-related GI toxicity?
GI protectants (H2 blockers, sucralfate), IV fluid therapy, appetite stimulants (mirtazapine, cyproheptadine), and enteral feeding (e.g., naso-oesophageal tube).
What is a preventive strategy for GI toxicity from doxorubicin in cats?
Pre-treatment with antiemetics (maropitant or metoclopramide) or avoiding doxorubicin if necessary.
What can be done if a specific chemotherapeutic agent causes significant GI toxicity in a cat?
The agent can be substituted (e.g., cyclophosphamide replaced with chlorambucil) or the dose can be lowered and administered more frequently.
How should treatment be adjusted in cases of GI lymphoma to avoid complications like perforation?
Start with vincristine alone and monitor response with ultrasound. Adjust therapy according to gastrointestinal wall thickness and risk of perforation.
What is extravasation, and why is it dangerous during chemotherapy?
Extravasation is the leakage of chemotherapeutic agents into surrounding tissue during IV administration, causing severe irritation and potentially requiring amputation if not managed properly.
What should be done immediately if extravasation occurs during chemotherapy?
Aspirate as much fluid as possible through the catheter.
How should vincristine extravasation be managed?
Infuse 3-5 ml of 0.9% sterile saline and apply warm compresses for 15 minutes, 3-4 times daily for 24 hours.
How should doxorubicin extravasation be managed?
Apply ice packs for 10-15 minutes every 2 hours for 72 hours, then 3-4 times daily for 10-14 days. If extravasation is minimal, ice for the first 24-48 hours may be sufficient.
What other treatments can help manage extravasation of chemotherapeutic agents?
Local instillation of hyaluronidase (300IU in 6ml saline) or applying topical DMSA.
What preventive measures should be taken to avoid extravasation?
- Use a clean, first-stick IV catheter, flushed with saline, not heparin. 2. Rotate limbs for consecutive treatments. 3. Use the smallest gauge catheters possible.
What is the correct procedure for IV catheter removal to prevent extravasation?
Flush the catheter with saline before removing it and use a swab during removal to avoid dropping residual drug on the cat’s coat.
What should be done if resistance, discomfort, or swelling is noticed during a chemotherapy infusion?
Stop the infusion immediately and investigate the cause.
Which chemotherapeutic agent is most commonly associated with anaphylaxis in cats?
L-asparaginase, especially when given intravenously (should be administered intramuscularly).
Which other chemotherapeutic agents have been associated with anaphylaxis in cats?
Doxorubicin and rarely cytosine arabinoside.
What are the signs of anaphylaxis in cats during chemotherapy?
Hypotensive shock, acute bronchospasm, and gastrointestinal signs like vomiting and diarrhoea (which may be haemorrhagic).
How should anaphylaxis during chemotherapy be managed?
IV fluids for circulatory support, adrenaline, antihistamines, bronchodilators, corticosteroids, gut protectants, and anti-emetics.
What are the preventive measures for anaphylaxis when administering chemotherapy in cats?
- Administer L-asparaginase intramuscularly. 2. Pre-medicate with chlorpheniramine before doxorubicin. 3. Avoid using the agent again if anaphylaxis has occurred.
Which chemotherapeutic agent is potentially nephrotoxic?
Anthracyclines, such as doxorubicin.
What should be considered when using drugs metabolized by the liver in cats?
Drugs like vincristine and doxorubicin should be used with caution in cases of liver dysfunction.
What are the side effects of hydroxyurea in cats?
Stomatitis, nail sloughing, alopecia, dysuria, pulmonary fibrosis, gastrointestinal and bone marrow toxicity, and methemoglobinemia at high dosages (>500 mg).
Why are cisplatin and carboplatin not recommended for use in cats?
They have severe toxicities in cats, which make their use inadvisable.
