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28 Cards in this Set
- Front
- Back
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Amidophosphoribosyl Transferase
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Rate limiting enzyme in the synthesis of purine nucleotides
-the reaction can be blocked by Amidophosphoribosyl Transferase Inhibitors |
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Functions of
Mercaptopurine & Thioguanine |
Used mainly in acute leukemia & chronic myelocytic leukemia
-need HGPRTase to be active |
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DNA Polymerase/DNA Chain Elongation Inhibitors
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-All must be converted to triphosphate nucleotides to be active
-All drugs in this group administered IV -induce myelosuppression as their use-limiting side effect |
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Cytarabine & Gemcitabine
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Cytidine-based anticancer agents
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Why gemcitabine shows a significantly longer half-life of (19 h) than cytarabine (3.6 h) ?
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due to inhibitory action of difluorodeoxycytidine triphosphate metabolite on
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Adenosine-based 3-halogenated anticancer agents
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Fludarabine, Cladribine & Clofarabine
-C-2 halogen renders these drugs relatively resistant to degradative action of adenosine deaminase - Of all these, Clofarabine has the longest half life time.(Most stable) |
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What do Taxanes &
Vinca alkaloids do? |
mitotic arrest & apoptosis (programmed cell death)
-Two classes of mitosis inhibitors |
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Taxanes(Paclitaxel & Docetaxel )
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-They bind to and prevent microtubular disassembly into tubulin monomers
Interrupting normal process of cell division |
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-------------claimed to be “the best-selling anticancer drug in history."
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Paclitaxel
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is the rational behind the combination therapy of capecitabine and Paclitaxel
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Paclitaxel's ability to up-regulate thymidine phosphorylation
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compare the water solubility of paclitaxel and Docetaxel ?
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Docetaxel has greater water solubility than that of paclitaxel because of presence of free C10-OH
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Vinca Alkaloids
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Block formation of mitotic spindle by preventing assembly of tubulin dimers into microtubules (opposite to action of taxanes)
-Act primarily in M phase of cancer cell cycle |
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--------------,------------------,& --------are the three marketed vinca alkaloids.
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Vincristine
Vinblastine Vinorelbine |
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The two important sections portions of the Vinca Alkaloids
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Catharanthine
Vindoline |
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List structural differences b/n Vincristine and
Vinblastine |
Vincristine lack bone marrow toxicity
-Vinblastine lack of neurotoxicity |
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Two marketedTopoisomerase drugs are
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Etoposide & Teniposide
-Increase degradation of DNA by interacting with topoisomerase II (similar to antibiotic antineoplastics |
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What do Camptothecins act upon?
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topoisomerase I
Examples are C9 (topotecan) or C10 (irinotecan) |
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Hormonal Anticancer Agents
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Used in management of hormone-dependent cancers
Often employed after surgery, radiation therapy and/or other chemotherapy |
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----------most ommonly Glucocorticoid used in combination therapy for leukemias & lymphomas
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Prednisone
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Antiandrogens
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Used to decrease action of endogenous androgens [testosterone & dihydrotestosterone (DHT)] in patients with prostate cancer
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Flutamide
Nilutamide & Bicalutamide (Casodex) |
-non-steroidal agents that act as competitive antagonists at androgen receptor
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Luteinizing Hormone-releasing Hormone (LHRH) Agonists
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Inhibit lutenizing hormone after initial stimulation thereby reducing production of testosterone
e.g Leuprolide Goserelin Buserelin |
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Leuprolide
Goserelin Buserelin |
(LHRH) Agonists used in prostate cancer therapy
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Antiestrogens or Estrogen Antagonists
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Compete with estrogen for binding on the estrogen receptor in breast cancer cells
Inhibition of estrogen action prevents transcription of genes that affect cell growth -Tamoxifen |
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Aromatase Inhibitors
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Used in treating postmenopausal breast cancer
Anastrozole Letrozole Exemestane 4-hydroxyandrostenedione (Formestane |
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Why Cancer drugs are the most toxic of any other pharmaceutical agents?
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They are non selective.Many available drugs are cytotoxic agents that act on all dividing cells, cancerous or normal .
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DNA Cross-linking Agents (Alkylators & Metallics)
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Primary target the actively dividing DNA molecule
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Nitrogen Mustards form a highly strained cyclic structure called
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Aziridinium ion
-Guanine is the preferred nucleic acid base involved in Mustard-Mediated Alkylation |
