Chemo Drugs 1/2 Flashcards
Phase 1 clinical trials
Determine dose and dose limiting toxicity
Phase 2 clinical trials
determine activity
phase 3 clinical trials
determine efficacy
Goldi-coldman hypothesis
neoplastic cell resistance to chemo occurs as a chance, spontaneous, event analogous to resistance of bacterial antibiotics
Skipper Hypothesis
ability of chemotherapy to cure cancer is inversely proportional to the tumor burden
Ondansetron should be avoided when
long QT sydnrome
ANC
total white count X (fraction of PMN + fraction of bands)
-any patient who develops fever greater than 385 and has ANC less than 500 must hospitalized and started on broad spectrum antibiotics until ANC greater than 500
Alkylating Agents bis(chlorethyl)amines Cyclophosphamide Mechlorethamine Chlorambucil (oral) Melphalan(oral) How do they work ?
- Drugs bind covalently to DNA
- cell cycle non-specific
- DNA drug interstrand and intrastrand crosslinks
- Bifunctional alkylating agents that preferentially alkylate the N-7 position of guanine
How do cancers develop resistance to alkylating agents?
enhanced DNA repair (nucleotide excision repair enzymes) or binding the alkylating agents to sulfur containing molecules
Cyclophosphamide Class: Cycle specificity: Macromolecular target: Bioactivation: MOA: Pharmacokinetics and metabolism: Side effects:
Class: bifunctional alkylating agent (oxazaphosphorine)
Cycle specificity: CCNS
Macromolecular target: DNA
Bioactivation: P-450 oxidase in liver
MOA: alkylates the N7 position of guanine and forms intrastrand and interstrand crosslinks
Pharmacokinetics and metabolism: Metabolites excreted in urine
Side effects: N/V, hairloss, myelosuppression(dose limiting toxicity), hematuria
Special features and dose modifications of Cyclophosphamide
- Hematuria
- administer drug in morning with 6-8 glasses water
- continuous bladder irrigation
- use of MENSA(uroprotective agent-thiol group of mensa binds toxic metabolites) - occasional occurrence of acute leukemia due to mutagenic effects of drugs
- no guidelines for dose modifications due to renal or hepatic dysfunction
What is cyclophosphamide used for?
- Breast Cancer
2. Non-Hodgkin’s lymphoma
Ifosfamide Class: Cycle specificity: Macromolecular target: Bioactivation: MOA: Pharmacokinetics and metabolism: Side effects:
Class: alkylating agent, isomer of cyclophosphamide
Cycle specificity: CCNS
Macromolecular target: DNA
Bioactivation: P-450 oxidase (same as cyclophosphamide)
MOA: DNA crosslinking
Pharmacokinetics and metabolism: excreted in urine
Side effects: Myelosuppression is dose limiting. At high doses: lethargy and confusion. N/V hairloss
What is always administered with ifosfamide?
MENSA
What do you use ifosfamide for?
- sarcomas
2. relapsed testicular cancer