082914 antineoplastics part two Flashcards
alkylating agents mechanism
introduce alkyl groups into DNA, RNA, proteins (DNA is likely the most important target)
causes DNA crosslinks, strand breaks, misreading of code
cell cycle specificity of alkylating agents
can be:
cell cycle non specific (also affect G0 cells)–ex are mechlorethamine, carmustine
cell cycle specific phase nonspecific-ex are cyclophosphamide
what is unique of the alkylating agents?
least selective of the antineoplastics (tend to kill tumor and normal cells equally)
toxicities of alkylating agents
mechlorethamine-nausea and vomiting, myelosuppresion
carmustine-nausea and vomiting, delayed myelosuppression
cyclophosphamide-nausea and vomiting, limited myelosuppression, alopecia
what are the typical side effects of alkylating agents in general? (not for specific drugs)
hematopoeisis suppression (often used as indicator of therapeutic effectiveness and normal cell recovery)
GI effects (damage to intestinal mucosa…nausea and vomiting
alopecia
affect RAPIDLY DIVIDING tissues most
what two drugs are examples of nitrogen mustards in alkylating agents?
mechlorethamine
cyclophosphamide
what drug is an ex of nitrosoureas in alkylating agents?
carmustine
mechlorethamine cell cycle specificity
cell cycle nonspecific
what is mechlorethamine used for
in combo therapy for Hodgkin’s and non-Hodgkin’s LYMPHOMA
breast, lung, ovarian cancer
MOA of mechlorethamine
bifunctional alkylating agent: produces DNA cross links highly reactive (disappears from blood in seconds to minutes)
what is the cell cycle specificity of cyclophosphamide
cycle specific phase nonspecific
what is unique about cyclophosphamide?
PRODRUG activated by liver cytochrome P450s
actual alkylating agent is phosphoramide mustard
toxicity of cyclophosphamide
bladder toxicity-sterile hemorrhagic cystitis (can be partially prevented with mesna)
what is good about cyclophosphamide?
very broad spectrum of activity, so used against wide variety of cancers
BREAST CANCER
cell cycle specificity of carmustine
cycle nonspecific
what is unique about carmustine?
crosses BBB very well
uses of carmustine
brain tumors, multiple myeloma, melanoma
when are antimetabolites most effective?
against tumors where cell proliferation is rapid
cell cycle specificity of antimetabolites
S phase specific
what are antimetabolites?
structural analogs of precursors of nucleic acid synthesis or other related pathways
MOA of methotrexate and what type of drug is it?
type: antimetabolite
MOA: binds to dihydrofolate reductase and prevents formation of tetrahydrofolate, which is needed for synthesis of dTMP
leucovorin rescue
high doeses of methotrexate are necessary to bind all dihydrofolate reductase
rescue host cells with leucovorin–leucovorin is folinic acid, which is a fully reduced folate that does not require to be reduced by DHFR (normal cells have increased ability to bring in leucovorin relative to tumor cells)
side effects of methotrexate
intestinal epithelium damage
bone marrow suppression
renal tubular necrosis
displaces other drugs from serum albumin
uses of methotrexate
acute lymphocytic leukemia
choriocarcinoma (methotrexate is #1 drug for this)
head neck breast lung
osteosarcoma
fluorouracil: type of drug and MOA
antimetabolite
pyrimidine analog that is activated in cells to FUTP which inhibits RNA synthesis. also activated to FdUMP which interferes with thymidylate synthase and ultimately DNA synthesis
side effects of fluorouracil
nausea, anorexia, diarrhea
myelosuppression
uses of fluorouracil
BROAD spectrum:
COLON, BREAST, stomach, pancreas, ovary, head, neck, bladder (mostly GI)
basal cell carcinoma
cytarabine: type of drug and MOA
antimetabolite
pyrimidine (cytidine) analog that competes for phosphoyrlation of cytidine; competes for incorrporation into DNA and causes chain termination
side effects of cytarabine
marked myelosuppresion (limits dose) neurotoxic
uses of cytarabine
acute leukemias (acute myelocytic leukemia for ex)
mercaptopurine: type of drug and MOA
antimetabolite
purine analog-converted in cells to ribonucleotide that inhibits RNA and DNA synthesis
sides effects of mercaptopurine
bone marrow depression
vomiting, nausea, anorexia
jaundice
uses of mercaptopurine
acute leukemias
TPMT is important for mercaptopurine b/c?
TPMT degrades mercaptopurine (6MP) to inactive form of 6 methyl MP. If person has non functional allele for it, has increased risk of serious bone marrow toxicity with normal dose
if pt has two copies of nonfunctional TPMT, then can’t tolerate the 6MP
hydroxyurea: type of drug and MOA
antimetabolite
inhibits ribonucleotide reductase (blocks conversion of ribonucleotides to dNTPs, preventing DNA synthesis
arrests cells then at G1-S point
major uses of hydroxyurea
granulocytic leukemia
side effects of hydroxyurea
hematopoietic depression
GI disturbances
examples of the vinca alkaloids, and what class of drug are the vinca alkaloids?
vincristine, vinblastine
class: natural products
MOA of vinca alkaloids
binds to tubulin, inhibiting proper formation of microtubules and mitotic spindle
arrests cells in metaphase
how are vincristine and vinblastine similar or different?
similar in that structurally related
different in their toxicities and their antitumor spectrum
side effects of vinblastine
strongly myelosuppressive
epithelial ulcerations
side effects of vincristine
significantly less bone marrow toxic. than vinblastine
alopecia, neuromuscular abnormalities (peripheral neuropathy)
uses of vinblastine
lymphomas, breast cancer
uses of vincristine
acute lymphocytic leukemia
lymphomas
Wilm’s tumor
neuroblastoma