10/9 Flashcards
Antineoplastic Agents Mechanisms of Action
Kill cells by apoptosis and necrosis
- Promote DNA and RNA damage
- Inhibit DNA repair
- Disrupt cellular metabolism
- Interfere with tubulin assembly/disassembly process
Normal cells affected by antineoplastic agents
Kills normal cells with a high grade fraction
- Gastrointestinal mucosa
- Bone marrow cells: often the dose limiting factor, want to avoid excess neutropenia and thrombocytopenia, should use CSF
- Hair follicles
- Ovaries
Cell Cycle Specific Agents
Depend on the duration of exposure
G1: steroid hormones, asparaginase
S: antimetabolites like methotrexate, 5-fluorouracil, 6-mercaptopurine
Often feature myelosuppression
G2: bleomycin, etopside
M: vinca alkoids like vincristine, taxanes like paclitaxel
Cell Cycle Non-specific Agents
Cumulative dose is important
- Alkylation Agents- feature myelosuppression
Nitrogen mustards: cyclophosphamide
Nitrosoureas: carmustine - Anthracycline antibiotics: doxorubicin, daunorubicin
- Monoclonal antibodies: rituximab
- Tyrosine kinase Inhibitors: imatinib
Cell Cycle Specific Agents: Glucocorticoid
- Class: Hormones
- Prototype: Glucocorticoid (Prednisone, dexamethasone)
- Mechanism of Action: G1, induce apoptosis in lymphoid malignancies
- Adverse Effects: body fluid retention, Hyperglycemia, weight gain, euphoria, confusion
- Indications: leukemia, lymphoma, myeloma, breast cancer , brain metastasis, spinal cord compression
Cell Cycle Specific Agents: Gonadal Hormones
- Class: Hormones
- Prototype: diethykstilbestrol, testosterone
- Mechanism of Action: G1, cytostatic rather than cytocidial, long term administration
- Adverse Effects-
Androgen: cholestatic jaundice
Estrogens: N/V, hypercalcemia, uterine bleeding - Indications-
Androgen: breast cancer
Estrogen: prostate cancer
Cell Cycle Specific Agents: Gonadal Hormone Antagonists
- Class: hormones
- Prototype: tamoxifen, flutamide
- Mechanism of Action- G1
Tamoxifen: estrogen receptor blocker, prevents growth of estrogen receptor positive cells
Flutamide: androgen receptor blocker - Adverse Effects-
Tamoxifen: hot flashes, fluid retention
Flutamide: gynecomastia - Indications-
Tamoxifen: breast cancer
Flutamide: prostate cancer
Cell Cycle Specific Agents: Gonadotropin Releasing Analogs
- Class: hormone
- Prototype: leuprolide, goserelin
- Mechanism of Action: G1 phase, decrease FSH and LH if constant doses
- Adverse Effects: transient flare of symptoms in patients with bone metastasis
- Indications: prostate cancer
Cell Cycle a Specific Agents: Aromatase Inhibitors
- Class: hormones
- Prototype: anastrozole
- Mechanism of Action: G1, inhibits formation of estrogens from androstenedione
- Adverse Effects: nausea, asthenia, headache, hot flashes
- Indications: advanced breast cancer
Cell Cycle specific Agents: L-asparaginase
- Class: misc. antineoplastic agents
- Prototype: L-asparaginase
- Mechanism of Action: G1, catalyze the hydrolysis of Asn to Asp and NH3, depletes serum of Asn which is necessary for lymphoid cells
- Adverse Effects: hypersensitivity, inhibition of protein synthesis leads to decrease in clotting factors, hypoalbumenia
- Indications: lymphoid malignancy, T cell leukemia, T Cell lymphoma
Cell Cycle Specific Agents: Methotrexate
- Class: antimetabolite
- Prototype: methotrexate
- Mechanism of Action: analog of folic acid, inhibits DHFR, compromised DNA replication since depleted A, G, and T
- Adverse Effects: myelosuppression, GI toxicity
- Indications:acute leukemia, breast cancer, non Hodgkin and T Cell lymphoma
Note: folinic acid is routinely given to decrease toxicity, glucarpidase (enzymatically inactivates methotrexate) given to patients with overdose of MTX secondary to decreased MTX clearance from renal insufficiency
Cell Cycle Specific Agents: 6-Mercaptopurine
- Class: antimetabolites
- Prototype: 6-mercaptopurine
- Mechanism of Action: S phase, inhibits purine metabolism following its activation from HGPRT, a purine analog, incorporated into DNA and RNA affecting replication, transcription, and stability
- Adverse Effects: bone marrow suppression
- Indications: acute leukemias (ALL and AML)
Note: resistant cells may lack HGPRT, other purine analogs like thioguanine, adenosine, pentostatin, and azathioprine
Cell Cycle Specific Agents: Cytarabine
- Class: antimetabolites
- Prototype: cytarabine
- Mechanism of Action: S phase, activated by tumor cell kinases to form a nucleotide that inhibits pyrimidine metabolism
- Adverse Effects: bone marrow suppression, N/V, micositis
- Indications: used in regimens for acute leukemias
Note: resistant cells may lack such kinases
Cell Cycle Specific Agents: 5-Fluorouracil
- Class:antimetabolite
- Prototype: 5-fluorouracil
- Mechanism of Action: S phase, activated to a metabolite that inhibits thymidylate synthesis, purine analog, affects DNA/RNA elongation, transcription, and stability
- Adverse Effects: diarrhea, bone marrow suppression, ulcerative stomatitis
- Indications: mainly in the treatment of solid tumors
Cell Cycle Specific Agents: bleomycin
- Class: antibiotics
- Prototype: bleomycin
- Mechanism of Action: G2, Glycopeptide mixture that alters nuclei acid functions via free radical formation
- Adverse Effects: bone marrow sparing, pulmonary fibrosis, skin thickening, hypersensitivity reactions
- Indications: Hodgkin’s and other lymphomas, squamous cell and testicular cancers