Antineoplastics- Antimetabolites Flashcards
Oral prodrug of 5-Fluorouracil catalyzed by thymidine phosphorylase
Capecitabine
DOC for childhood ALL
6-mercaptopurine (6-MP)
AE: Renal damage due to crystal deposits in tubules
Methotrexate
Causes Hand/Foot Syndrome
5-Fluoruracil
Prodrug that inhibits Ribonucleotide Reductase (RNR) and causes chain termination
Gemcitabine
No drug interaction with Allopurinol
6-thioguanine (6-TG)
Metabolized by Xanthine Oxidase and Thiopurine Methyltransferase
6-Mercaptopurine
Not useful in patients with HGPRT deficiency (Lesch Nyhan Syndrome)
6-mercaptopurine
Useful for colorectal cancer
Capecitabine and 5-Fluorouracil
Useful for Pancreatic cancer
Gemcitabine
Catabolized by Dihydropyrimidine dehydrogenase; deficiency causes Life-threatening diarrhea, myelosuppression, neurotoxicity
5-Fluorouracil
Converted to polyglutamates to inhibit DHF Reductase
Methotrexate
Used with Methotrexate to rescue THF to prevent bone marrow toxicity
Leucovorin (folinic acid)
Combination therapy for colorectal cancer
5-Fluorouracil + Leucovorin
First line treatment for metastatic colorectal cancer
Capecitabine
AE: HUS and TTP
Gemcitabine
Can be used topically for ketatoses and Basal Cell Carcinoma
5-Fluorouracil
Antimetabolites are cell cycle specific for which phase?
S-phase
Decreases intracellular GMP to inhibit DNA synthesis
6-thioguanine
Hypoxanthine analog
6-mercaptopurine
Converted TIMP to inhibit de novo purine synthesis
6-mercaptopurine
Dose must be reduced if given with Allopurinol
6-mercaptopurine
If deficient in Thiopurine Methyltransferase, which 2 drugs would require a lesser dose?
6-mercaptopurine and 6-thioguanine
Neurotoxicity with Intrathecal administration
Methotrexate
Competitively inhibits alpha and beta DNA Polymerase and inserts itself into nucleic acid
Cytarabine
Only useful for hematologic malignancies; not useful against solid tumors
Cytarabine
Folate Analog
Methotrexate
Purine Analogs
6-Mercaptopurine and 6-Thioguanine
Pyrimidine Analogs
5-Fluorouracil, Capecitabine, Deoxycytidine Analogs (Gemcitabine and Cytarabine)