click below
click below
Normal Size Small Size show me how
Oncology II
Specific Cell Cycle Cytotoxic Drugs: Folate Antimetabolites
| Term | Definition |
|---|---|
| what is the MOA of folate antimetabolites? | - block the di-hydrofolate reductase --> block purine/ pyrimidine synthesis --> block the folic acid cycle - S PHASE |
| which phase dose the folate antimetabolites act on? | the S-phase |
| What are some recommendation to minimize the risk of folate antimetabolites toxicities? | - give folic acid & vitB12 |
| what is the difference between leucovorin and levo-leucovorin? | LEVOleucovorin is the ACTIVE L-isomer of leucovorin - the dose of LEVOleucovorin = 1/2 leucovorin |
| How dose leucovorin minimize the toxicity of high-dose methotrexate? | - leucovorin is a folic acid active form ( folinic acid) - bypass the activation step by dihydrofolate reductase enzyme - |
| What is a common class side effect ( folate antimetabolites)? | - NEPHORTOXOCITIY - hepatotoxicity |
| Which side effect of folate antimetabolites is dose dependent vs. chronic use? | - Nephrotoxicity: DOSE dependent - hepatotoxicity: chronic use |
| what is the MOA of LEUCOVORIN while used with Fluorourical vs. methotrexate? | - Augmentation vs. rescue |
| which cytotoxic drugs act on the S-phase? | - folate antimetabolites - pyrimidine antimetabolites - Topoisomerase I inhibitors |
| List the common folate antimetabolites drugs? | 1- methotrexate 2- pemetrexted 3- pralatrexate |
| which folate antimetabolite causes dermatological toxicity? | PEMEtrexted and Methotrexate ** premeditated with steroid |
| what are some recommendation to manage PEMEtrexted and PRALAtrexted toxicity? | -Give: 1- VitB-12 2- Folic acid ** for PEMEtrexted : dexamethasone 2/2 dermatological side effects |
| What is the difference in methotrexate dosing in rheumatoid arthritis vs. Cancer? | - RA: low- dose/ week vs. Cancer: high-dose/ day |
| what is the cutoff of high dose methotrexate? | 1- >= 500mg/m2/ dose is considered high dose 2- > 1 gram/m2 is considered nephrotoxic |
| what are some management considerations to minimize the risk of methotrexate when given at high dose >= 500mg/m2/dose? | 1- GIVE methotrexate with LEVOleucovorin until methotrexate level is <0.05-0.1 MICROMOLAR 2- HYDRATION 3- IV Na-bicarbonate ( alkalinize the urin) ( folic acid + bicarbonate = alkalinizie) |
| What are some complications that increases the risk of methotrexate toxicity 2/2 reduction in clearance and build up of the drug? | - 3rd spacing ds 1- ascites 2- pleural effusions 3- severe edema |
| what is the antidote of methotrexate toxicity? | Glucarpidase turns methotrexate into inactive metabolites: 1- DAMPA 2- Glutamate |
| which DDI effect the clearance of methotrexate? | 1- NSAIDS ( acid) 2- PPI ( reduce acid) 3- beta lactamease 4- salicylate ( acid) 5- sulfonamide Ab ( sulfa) 6- probenecid ( uric acid reducer) |
| which folate antimetabolites causes hand-foot syndrome? | methotrexate |
| Methotrexate Boxed Warnings: 1- myelosuppresion: 2-nephrotoxic 3- hepatotoxic 4- pregnancy 5- Tumor lysis syndrom | - Myelosuppression: 1- aplastic anemia, stomatitis, interstitial pneumonitis - nephrotoxic: - hepatotoxic Fibrosis/ cirrhosis--->> Ascites/ pleural effusion - Dermatological: SJS and TEN - pregnancy: fetal death and teratogenic - tumor lysis synd |