CHEMOTHERAPY DRUGS Flashcards
types of cancer treatment
surgery
radiation
chemotherapy
treatment will depend on the type of cancer, progression of the disease, health of the pt and pt choice
chemotherapy
the treatment of cancer with one or more cytotoxic drugs
often used in conjunction with other treatments (radiation therapy, surgery etc.)
most common side effects of chemotherapy
myelosuppression (decreased production of blood cells, hence also immunosuppression)
mucositis (inflammation of the lining of the digestive tract)
alopecia (hair loss)
chemotherapy moa
act by killing cells that divide rapidly, one of the main properties of cancer cells, this means that chemotherapy also harms cells that divide rapidly under normal circumstances: cells in the bone marrow, digestive tract and hair follicles
problems with chemotherapy
- treatments are non-specific, attack healthy cells as well as cancer cells
- cancers are heterogenous - genes mutated so bits of some cancers or metastases may be resistant to some drugs
indicators that the cancer has developed resistance to therapy
- decreased drug uptake/increased efflux
- enhanced tolerance of DNA adducts
- enhanced repair of DNA adducts
- increasing drug deactivation by intracellular glutathione
- toxicity to normal cells
types of anticancer drugs PATAAT
platinates
anthracyclines
taxanes
alkylators
antimetabolites
topoisomerase inhibitors
how do PATAAT drugs act
act by inducing cellular apoptosis (programmed cell death)
alkylation
transfer of an alkyl group from one molecule to another - alkylation of DNA is used in chemotherapy to damage the DNA of cancer cells
alkylating agents moa
attaches to an alkyl group (Cn H2n+1) to the guanine base of DNA, at the number 7 nitrogen atom of the purine ring
consequences of alkylating agents
- DNA fragmented by repair enzymes in their attempts to replace the alkylated bases
- addition of the alkyl group to the base causes the mispairing of the nucleotides leading to mutations
- alkylating agents cause formation of cross-bridges, bonds between atoms in the DNA - 2 bases are linked together by an alkylating agent that has 2 DNA binding sites. cross-linking prevents DNA from being separated for synthesis or transcription. as this is necessary on DNA replication, the cells can no longer divide
6 groups of alkylating agents
nitrogen mustards
ethylamines
alkylsulfonates
triazenes
piperazines
nitrosureas
alkylating-like drugs: platinum-based drugs
CISPLATIN AND CARBOPLATIN
- platinum analogues act similarly to alkylating agents
- these agents do not have an alkyl group, but damage DNA
- they permanently coordinate to DNA to interfere with DNA repair
cisplatin effect on DNA
- replication inhibition
- transcription inhibition
- cell-cycle arrest
- DNA repair
- cell death
cisplatin side effects
- small therapeutic window
- neurotoxic (nerve damage) - visual perceptions, hearing disorders
- nephrotoxic - related to reactive oxygen species
- nausea and vomiting - often given with anti-emetics
- myelotoxicity - bone marrow suppression
carboplatin
- delivers the same drug as cisplatin but with chloride ligands replaced with bidentate dicarboxylate
- preferred first line with ovarian and small cell lung cancer
- takes less time to administer than cisplatin
- solution (10mg/ml)
satraplatin
- first platinum anti-cancer drug that can be administered orally
- most platinums are usually given in combination with other drugs
- indicated for prostate cancer
anthracycline-based drugs - intercalating drugs
- natural products derived from various strains of streptomyces bacteria
- four-ring structure linked via glycoside bond to daunosamine
- doxorubicin = for many solid tumours
anthracycline side effects
- nausea and vomiting, extravasation can cause tissue necrosis, bone marrow depression/immunosuppression, myelosuppression, infertility, dehydration
- myocardial toxicity from cumulative doses of around 450-500mg/m2 - patients need cardiac monitoring
- 1 in 2 patients in every 100 develop acute myelogenous leukaemia or myelodysplastic syndrome. risk even higher for those concurrently treated with cyclophosphamides or radiotherapy.
actionmycin D
- inhibits transcription
- it does this by binding DNA at the transcription initiation complex and preventing elongation of RNA chain by RNA polymerase
microtubules function
- cell shape
- cell movement
- movement of cargo within cell
- mitosis
spindle poisons
alters structure and function of microtubules
example of spindle poisons: vincristine, used for…
- acute leukaemia’s
- Hodgkin’s lymphoma
- non-Hodgkin’s lymphoma
- small cell lung cancer
adverse effect of vincristine
peripheral neuropathy
cisplatin structural effect on DNA
binds to DNA and causes a critical 45 degree bend