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10 Cards in this Set
- Front
- Back
Antimetabolties are CCS or CCNS?
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CCS - target S phase
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Methotrexate mechanism of action?
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dihydrofolate reducatase inhibitor leads to decreased synthesis of thymidylate synthesis, purine nucleotides and amino acids.
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Mercaptopurine and thioguanine mechanism of action?
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Purine antagonists - prodrugs needs HPGRT to activate to cytotoxic form. inhibit denovo purine and pyrimdine synthesis
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5-FU mechanism?
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Pyrimidine antagonist - gets converted to FdUMP which inhibits thymidylate synthase (suicide inhibition)
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methotrexate toxicity?
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Myelosuppression, skin adn GI mucosa toxic reduced by folinic acid (leucovorin rescue). Pulmonary infiltrates.
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leucovarin rescue with mtx?
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Rescue with mtx - leucovorin needs to be actively tranported into cells to reduce mtx cytotoxicity. normal cells can transport it and cancer cells cannot.
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Resistance to mercaptopurine?
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Loss of HGPRT
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Mercaptopurine toxicity?
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Myelosuppression, cholestasis, pancreatitis, oral/GI ulcers. Allopurinol decreses tox. mostly well tolerated.
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methotrexate resistance/
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DHFR mutations and decreased polyglutamate formation
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leucovorin and 5-FU/
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enhances formation of ternary complex and thus efficacy of 5-FU. leads to increased toxicity in non-cancerous tissue.
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