ANTICANCER DRUGS Flashcards
(153 cards)
Indications for Chemotherapy:
Chemotherapy is presently used in four main
clinical settings:
- Primary (induction) chemotherapy .
- Neoadjuvant chemotherapy .
- Adjuvant chemotherapy .
- Site-directed chemotherapy.
Primary Chemotherapy
• Chemotherapy administered as the primary treatment in patients who present with advanced cancer for which no alternative treatment exists. • The goals of therapy are to: 1. Relieve tumor related symptoms. 2.Improve overall quality of life. 3.Prolong time to tumor progression.
Neoadjuvant Chemotherapy
• Chemotherapy is administered before surgery.
• The goal is to reduce the size of the primary
tumor so that surgical resection can then be
made easier.
Adjuvant Chemotherapy
• Administration of chemotherapy after local
treatment modalities (e.g. surgery) has been
performed.
• Destroys microscopic cells that may be present
after local treatment modalities has been done.
• Reduces the incidence of both local and systemic
recurrence and to improve the overall survival of
patients.
Site-Directed Chemo.
2 types?
- Direct instillation into sanctuary sites (intrathecal or peritoneal)
- Regional perfusion of the tumor (e.g Intra-arterial)
Growth Fraction
what is it?
what type of tumor cells are more responsive to chemo?
• Growth fraction is the percentage of actively
dividing cells at any given point in time.
• Malignant neoplasms with high growth fraction
(E.g. leukemia and lymphoma) are more sensitive to chemotherapeutic drugs.
• Low growth fraction tumors (Solid tumor e.g. carcinomas of the colon, lung cancer) are less
responsive to chemotherapeutic drugs.
What is the standard approach in the management of many tumor cells?
COMBINATION CHEMO -
1. Provides maximal cell kill within the range of
toxicity tolerated by the host for each drug.
2. Drug combinations are effective against a broader
range of cell lines.
3. Some combinations of anticancer drugs appear to
exert synergistic effect.
4. May prevent or slow the subsequent development of
cellular drug resistance.
Log Kill Hypothesis?
- the action of a cytotoxic drug follows first order kinetics!
- A given dose of chemo kills a constant fraction of a tumor cell population (rather than a constant number of cells)
• Repeated doses of chemotherapy -with
appropriate frequency- are required to eradicate
the tumor cells.
Common AE due to chemo. and tx?
most chemotherapeutic agents have toxic effects on normal cells, particularly those with rapid rate of turnover, such as bone marrow and mucous
membrane cells.
• Nausea and vomiting (treated with 5HT3 blockers and NK1 inhibitors). • Stomatitis • Alopecia • Myelosuppression (Filgrastim is used to treat neutropenia).
Strong myelosuppressors
"My strong Vin CADD" Cytarabine Alkylating agents Doxorubicin Daunorubicin Vinblastine
Moderate myelosuppression
Carboplatin
Methotrexate
5-FU
Mild Myeosuppression
“BAV”
Bleomycin
Vincristine
Asparaginase
Specific AE:
Doxorubicin
Cyclophosphamide and ifosphamide
Bleomycin
• Doxorubicin causes cardiotoxicity.
• Cyclophosphamide and ifosphamide cause
hemorrhagic cystitis (Mesna)
• Bleomycin causes pulmonary fibrosis.
Treatment-induced neoplasms are especially a problem after therapy with
alkylating agents.
Toxicity: minimizing AE: Leucovorin Mesna Dexrazoxane Filgrastim Amifostine
• Leucovorin rescues bone marrow from methotrexate.
• Mesna reduces hemorrhagic cystitis caused by cyclophosphamide and ifosfamide.
• Dexrazoxane reduces anthracycline (doxorubicin and daunorubicin)-induced
cardiotoxicity.
• Filgrastim reverses neutropenia caused by many
anticancer agents.
• Amifostine is a cytoprotective agent that reduces renal toxicity caused by cisplatin.
Most important efflux pump for multdrug resistance?
P-Glycoprotein (permeability glycoprotein) AKA MDR1
what cells are more sensitive?
cell cycling within the cell cycle..Not cell in Go phase.
Cell cycle specific vs Cell cycle non specific
• cell cycle-specific drugs are most effective in hematologic malignancies and other tumors in which a large proportion of the cells are proliferating or are in the growth fraction.
• Cell cycle-nonspecific drugs are useful in lowgrowth
fraction solid tumors as well as in highgrowth-fraction
tumors.
Cell Cycle specific agents?
"Bleo CAME around" Antimetabolites Microtubule inhibitors Epipodophyllotoxins Camptothecins (TOPOTECAN, IRINOTECAN) Bleomycin
Cell cycle Nonspecific agents
“APA”
Alkylating agents
Platinum coordination complexes
Antitumor antibiotics
Antimetabolites
- Block S phase
Folate analogs
Purine analogs
Pyrimidine analogs
Methotrexate (MTX) MOA
- converted intracellularly to methotrexate polyglutamates which bind and inihibit DIHYDROFOLATE REDUCTASE.
- This results in inhibition of the synthesis of THF which is involved in denovo synthesis of:
- deoxythymidylate nucleotides → Inhibition DNA
synthesis. - Purine nucleotides → Inhibition DNA and RNA
synthesis
Leucovorin
MOA
• Leucovorin is N5-formyl-THF.
• Antidote to drugs that decrease levels of folic
acid, such as methotrexate, to rescue the bone
marrow.
• Leucovorin provides the normal tissues with the
reduced folate, thus circumventing the inhibition
of DHFR
Methotrexate Clinical applications?
• Breast cancer, head and neck cancer, osteogenic sarcoma, bladder cancer, choriocarcinoma,
primary central nervous system lymphoma and
non-Hodgkin’s lymphoma.