Chemotherapy Flashcards
(34 cards)
Therapeutic Index for Chemotherapy?
very narrow, less than two-fold
BAG Signs
Bone Marrow
Alopecia
Gastrointestinal
How does chemotherapy target specific cells?
based on rate of division of the target cells
% of dogs that will die from cancer
25%
Is cancer always malignant or life threatening?
no (lipomas, sebaceous adenomas)
Metabolic Derangements of Cancer (3)
-Hypercalcemia (–> changes in renal blood flow and neuromuscular conjunctions)
-Hypoproteinemia
-Hyperproteinemia
6 Possible Routes of Administration for Chemotherapy Drugs
- IV
- Oral
- Intralesional
- Intracavitary
- IM
- SQ
What is the systemic effect of chemotherapy dependent on?
absorption of drug into the bloodstream
With which route of administration is absorption the most variable?
oral
Do we see alopecia in dogs and cats?
Not really because of the differences in hair follicles between humans and animals (exception would be the dogs that need groomed)
What % of IV drugs are absorbed?
100% (you literally put the drug in the bloodstream)
Advantages of Oral Administration
no specialized medical care required, can reach people who may not normally have access
Disadvantages of Oral Administration
bioavailability can be affected by many other factors (transit time (incl. short bowel syndrome), pH, presence of food, how fatty is that food, owner compliance, etc)
Intralesional Administration
directly administer immune-stimulating agents into the cancerous lesion
Intracavitary Administration
results in a higher concentration of the drug being locally absorbed at the site of disease
Intravascular (Liquid) Tumors
flowing in the bloodstream or lymphatics; highly dependent on protein binding
ex: lymphoma, leukemia, and myeloma
Extravascular (Solid) Tumors
tumors that must be perfused by the bloodstream, therefore are highly dependent on vascularity
Why is it difficult to get very large tumors to respond to chemotherapy?
areas of poor or even avascularization so cannot get the drugs to their target; these tumors also often develop a necrotic center
Antineoplastic Drug Distribution and Interstitial Pressure
requires interstitial pressure to diffuse out of the bloodstream and into the tissues
Main target of antineoplastic drugs?
DNA (so remember your drug needs to be able to cross certain membranes to gain access to the nucleus)
Confounding Variables at the Anatomic Level (4)
- Sanctuary Sites
- Third Spacing
- Aberrant Blood Vessels
- High interstitial pressures
Sanctuary Sites
areas of the body protected by an additional barrier, such as the blood-brain, eye, or prostate
Third Spacing
accumulation of fluid from the blood within areas of the body that normally contain little fluid and anything within becomes non-functional (so if drugs are here, they’re not getting where you want them to go)
Effect of High Interstitial Pressure?
less chemotherapy getting where it needs to go (it won’t be able to leave the blood vessels)
