Breast Cancer Drug Dase Oct 9 Flashcards
WHat are the 4 major cancer drugs we’re concerned about?
What class do they all fall under?
Cyclophosphamide
5-fluorouracil
Anthracyclines
Paclitaxel
These are all cytotoxic durgs
What do cytotoxic cancer drugs do?
They target rapidly proliferating cells
How does cyclophosphamide work?
It alkylate DNA, RNA and proteins
specifically the N-7 position of guanine in DNA
When you alkylate the DNA it forms DNA cross linkage, which means the cell can’t replicate it’s DNA and it will die
Is cyclophosphamide cell cycle specific or nonspecific? In what stage is it most tosic?
Because it can alkylate the DNA whenever DNA is present (which is always), it is cell cycle nonspecific
it is most toxic to cells in S phase
What is the mechanism of action for 5-fluorouracil?
It inhibits Thymidilate synthase, so you don’t get the synthesis of dTMP from dUMP
the cell therefore can’t replicate its DNA and dies
Is 5-fluorouracil cell cycle specific or nonspecific?
it’ cell cycle specific to S phase
What is the mechanism of action for the Anthracyclines?
They intercalate the DNA and block the action of topoisomerase 2
It also blocks helicase, which leads to the development of free radicals, causing damage and eventually cell death
Are anthracyclines cell cycle specific or nonspecific?
They are cell cycle nonspecific
What is the mechanism of action for Paclitaxel?
It stabilizes microtubules, which may sound like a good thing, but it means that you get spindle fibers that grow and grow and never shrink
this means the chromatids can’t separate during mitosis and the cells dont’t divide
Eventually this leads to cell death
It paclitaxel cell cycle specific or nonspecific?
Cell Cycle Specific for M phase
What are some side effects common to all cytotoxic antineoplasm medications?
neutrophenia - the neutrophils are killed
immune suppression
hair loss - follicles rapidly divide
birth defects and decreased fetal growth
Nausea/Vomiting/Diarrhea since GI cells rapidly divide too
Which side effect is the dose limiting effect in cytotoxic cancer treatment?
THe bone marrow suppression
However, it’s the GI symptoms that are the biggest issues for noncompliance
