Antineoplastic Agents Flashcards
Cyclophosphamide
Alkylating Agent
Bischloroethyl amine
Anti-Tumor, less highly reactive derivative
Alkylating activity requires activation in liver or tumor tissues
Treats autoimmunity as well
Mechlorethamine
Alkylating agent
Bischloroethyl amine
Nitrogen mustard (prototype of alkylating agents)
Analog of mustard gas
Highly Reactive DNA alkylating/damaging agent
Necrosis if given as IV administration
A part of the MOPP regiment (Hodgkin’s disease) with vincristine, procarbazine, and prednisone
Nitrosoureas
Alkylating Agent
Little cross-resistance with other alkylating agents
Crosses blood-brain barrier
Useful against brain tumors
Compare with bichloroethyl amines
Procarbazine
Alkylating Agent
Metabolized to alklating and free radical (reacting) intermediate
Effective in MOPP regimen against Hodkin’s disease
Little cross-resistance with other antineoplastic agents
Leukemogenic (5-10% risk with MOPP regimen), alternative is ABVD regimen
Highly toxic
cisplatin and carboplatin
Platinum Coordination complex
Reacts with DNA causing displacement of helix/cross-linking
Blocks the DNA repair enzyme to fix the DNA damage
2 Chlorides allow cross link to occur
Cell cycle nonspecific, DNA crosslinking
May inhibit DNA biosynthesis
Useful in various combination regimens
Ovarian and testicular cancer
Clinical toxicity: NEPHROTOXIC (hydration) and ACOUSTIC NERVE DYSFUNCTION
methotrexate
Anti-tumor Antimetabolite
Folic acid analog
Dihydrofolate reductase inhibitor (DHFR)
Blocks synthesis of DNA, RNA and precursors
Accumulates in cells as Polyglutamate derivative
S phase-specific!!
Structures contains extra methyl that causes disfunction
Mechanisms of Resistance
- Amplification of DHFR gene
- DHFR gene mutation
- Decreased uptake
- Increased drug efflux
FOLINIC ACID “rescues” aids in bone marrow recovery
Leucovorin-folinic Acid Rescue
Rescues body from methotrexate toxicity by aiding in bone marrow recovery,
Cycled after methotrexate use
Fluorouracil (5-FU)
Pyrimidine Antagonist
Metabolite Fluorodeoxyuridine monophosphate (FdUMP) inhibits thymidylate synthetase– THYMINELESS DEATH
Metabolites incorporated into newly synthesized DNA and RNA
S phase-specific
capecitabine
Pyrimidine Antagonist
Oral prodrug of fluorouracil
Preferentially activated in tumor tissues (thymidine phosphorylase)
Approved for COLON CANCER and REFRACTORY BREAST CANCER
- Due to tumor cells having a high lvl of thymidine phosphorylase
Enzymes for Metabolism: - Carboxylesterase (Capecitabine-- 5-DFCR) - Cytidine Deaminase (5-DFCR---5 DFUR) - Thymidine Phosphorylase (5-DFUR--5-FU) - Dihydropyrimidine dehydrogenase
Cytarabine (cytosine arabinoside), araC
Pyrimidine Antagonist
Converted into araCMP, then to araCTP
araCTP is an inhibitor of DNA synthesis, also incorporated into DNA leading to mutations/DNA strand breaks
Metabolic activation requires Deoxycytidine kinase
Mutational loss of deoxycytidine kinase: MECHANISM of TUMOR CELL RESISTANCE
6-mercaptopurine/
Purine Antagonist
Metabolites inhibit de novo purine synthesis (masquerade as normal base)
Interfere with DNA and RNA synthesis
Fraudulent base incorporation (mismatches, strand breaks)
S-phase specific
Activated by conversion to NMPs, NTPs, via hypoxanthine-guanine phosphoribosyl transferase (HGPRT)
Down regulation of HGPRT: RESISTANCE to MEDICATION
INACTIVATED by xanthine oxidase
LOW BIOAVAILABILITY when administered with Cow’s Milk (high xanthine oxidase)
Enhanced with ALLOPURINOL, due to allopurinol inhibiting xanthine oxidase (look to lower dosage)
6-thioguanine
Purine Antagonist
Metabolites inhibit de novo purine synthesis (masquerade as normal base)
Interfere with DNA and RNA synthesis
Fraudulent base incorporation (mismatches, strand breaks)
S-phase specific
Activated by conversion to NMPs, NTPs, via hypoxanthine-guanine phosphoribosyl transferase (HGPRT)
Down regulation of HGPRT: RESISTANCE to MEDICATION
bleomycin
Anti-tumor Antibiotic
Main cytotoxic action is DNA strand Scission
PULMONARY TOXICITY (pulmonary fibrosis) at large doses
NO significant myelosuppresion (allows in combination regimen (ABVD, (doxorubicin, bleomycin, vinblastine, dacarbazine) in Hodgkin lymphoma
Natural Product: “anaphylatic” reactions, administer small test dose to check first
daunorubicin
Anti-tumor antibiotic and Topoisomerase Inhibitor
Anthracyclines
Used with broad spectrum of activity
DNA intercalation (mutagenic, carcinogenic)
DNA topoisomerase II binding, DNA scission
Irreversible cardiac toxicity at HIGH DOSES
- Heart monitoring REQUIRED
doxorubicin
Anti-tumor Antibiotic
Anthracycline
Widely used with broad spectrum of activity
DNA intercalation (mutagenic, carcinogenic)
DNA topoisomerase II binding, DNA scission)
IRREVERSIBLE CARDIAC TOXICITY at HIGH DOSES (requires heart monitoring when administered)
Part of ABVD regimen for Hodgkin and other lymphoma