Adverse Effects of Cytotoxic Drugs Flashcards
What are the 4 main adverse effects of cytotoxic drugs?
Myelosuppression, GI toxicity, Poor hair growth/hair loss, Drug extravasation.
Why does myelosuppression occur? What happens to blood cells?
Bone marrow stem cells are affected by drugs, usually a neutropenia (lowest 7d post dose), and a thrombocytopenia (platelets lowest 10d after dose).
When should myelosuppression be monitored?
Check CBC before every dose of myelosuppressive drug given (usually once a week)
If neutrophil count drops <2 x 10^9/L, what should you do?
Delay next dose and retest 3-7 days later.
At what neutrophil count would you delay the next dose of myelosuppressive drugs and retest 3-7 days later?
<2 x 10^9/L
If neutrophil count drops <1 x 10^9/L, what should you do?
May need prophylactic antibitoics, or if sick may need hospitalisation. Reduce the dose.
At what neutrophil count might you need to administer prophylactic antibitoics, or if sick may need hospitalisation, and also consider reducing the dose of myelosuppressive drugs?
<1 x 10^9/L
Why is GI toxicity adverse effects dangerous? What types of GI toxicity effects might you see in an animal with adverse effects from cytotoxic drugs?
May allow bacteria to get through BM. May see vomiting (central or peripheral), Diarrhoea, Anorexia.
How would you prevent/treat vomiting in an animal with adverse effects to cytotoxic drugs?
Vomiting - bland diet, anti-emetics (maropitant, metclopramide, ondansetron), and gut protectants (sulcralfate, omeprazole)
How would you prevent/treat diarrhoea and anorexia in an animal with adverse effects to cytotoxic drugs?
Diarrhoea - bland diet, metronidazole, fluids if severe.
Anorexia - Maropitant for nausea, appetite stimulant (cyproheptadine)
What is drug extravasation? Can you think of any drugs that are particularily bad for causing a reaction?
When a drug goes outside the vein, it can be very irritating. Vincristine/Vinblastine (skin sloughing) and Doxorubicin (severe tissue necrosis) particularily bad.
How can you try and prevent drug extravasation?
Always use cleanly placed I.V. catheter which is taped securely, flush before and after with 0.9% saline.
How would you treat drug extravasation of Vincristine/Vinblastine?
Hot compress, hyaluronidase
How would you treat drug extravasation of Doxorubicin?
Ice, dexrazoxane
