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Antineoplastics - Bauer
n/a
134
Pharmacology
Professional
02/12/2010

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Term
what are the acute side effects associated with antineoplastics?
Definition
1)bone marrow toxicity - inf./hemorrhage
2)GI mucosa toxicity - diarrhea
3)Hair follicle toxicity- hair loss
4)Germline cell toxicity - infertility
Term
what are the chronic side effects associated with antineoplstics?
Definition
cardiomyopathy
neurotoxicity
GI tract distress
nephrotoxicity
mutagenesis
carcinogenesis
Term
why do antineoplastics have limited effectiveness?
Definition
1)they only target cells in the cell cycle/proliferating
2)cells become resistant to therapy after rounds of chemo
Term
why do antineoplastics have limited effectiveness?
Definition
1)they only target cells in the cell cycle/proliferating
2)cells become resistant to therapy after rounds of chemo
Term
how do alkylating agents work?
Definition
they alkylate DNA leading to cell death
Term
How do antimetabolites work against cancer?
Definition
they inhibit RNA and DNA function
Term
what is the most toxic way that alkylating agents work?
Definition
crosslinking BETWEEN DNA strands
Term
what is the mechanism of mechloraethamine?
Definition
alkylation within DNA at N7 of guanine
BIFUNCTIONAL AGENT
Term
what are the side effects of mechloraethamine?
Definition
nausea and vomiting
STRONG VESICANT
Term
what are the mechanisms of resistance to mechloraethamine?
Definition
1)*DECREASED ACTIVE TRANSPORT - required for drug to get into cell
2)increased gluthione
3)increased DNA repair
Term
what are the used of mechloraethamine?
Definition
1)combo therpy for Hodgkins' (MOPP)
2)cutaneous T cell lymphoma
Term
what is mechanism of action of cyclophosphamide?
Definition
alkylation of DNA
*requires metabolism by CYP2B
Term
what are the side effects of cyclophosphamide?
Definition
bone marrow insufficiency
**alopecia
**hemorrhagic cystitis
Term
what is the mechanism of action of Melphalan?
Definition
alkylation within DNA at N7 on guanine
Term
what is important about the side effects of Melphalan?
Definition
1)No alopecia or changes in renal/hepatic function at standard dose
2)Less freq. nausea and vomiting compared to other alkylating agents
Term
How is resistance developed to Melphalan?
Definition
decrease in active transport
Term
Busulfan is a ________ agent
Definition
alkylating
Term
what are the side effects of Busulfan?
Definition
skin pigmenation - appear as freackles but get larger/darker
pulmonary fibrosis
adrenal insufficiency
Term
what is Nitrosureas used to treat?
Definition
high grade gliomas
Term
what is the only alkylating agent that can cross the BBB?
Definition
Nitrosureas
Term
what is the Carmustine Wafer?
Definition
implanted in patients to help treat high grade gliomas
Term
what is the target of Nitrosureas?
Definition
alkylation of O6 gunanine leading to G-C crosslinks
BIFUNCTIONAL alkylating agent
Term
what is responsible for resistance to Nitrosureas?
Definition
increased AGT activity
*decreased in 30% of primary gliomas so sensitive to treatment
Term
what phase of the cell cycle is highly targeted by antimetabolites?
Definition
S phase- where DNA is synthesized
Term
what antimetabolite is a folate antagonist?
Definition
methotrexate
Term
what is the mechanism of methotrexate?
Definition
folic acid analog which reversibly inhibits dihydrofolate reductase resulting in decreased dTMP
Term
what all does methatrexate cause decreased production of?
Definition
adenine, guanine, thymidine, methionine, serine
Term
what is the most prominent use of Methotrexate?
Definition
Burkitt's lymphoma in kids
Term
what are most drug interaction with methotrexate due to?
Definition
its high affinity for plasma albumin
Term
what are the side effects of methotrexate?
Definition
bone marrow suppression
GI
alopecia
dermatitis
**NEPHROTXICITY - use leucovorin rescue!!
Term
what should be used with methotrexate to help with nephrotoxicity?
Definition
leucovorin rescure
Term
what is responsible for resistance to methotrexate?
Definition
1)impaired active transport
2)reduced affinty of DHFR
3)increased conc. of DHFR
4)**decreased ability to synthesize METHOTREXATE POLYGLUTAMATES
5)increased MDR protein
Term
what does leucovorin bypass?
Definition
DHFR
Term
what does 6-Mercaptopurine inhibit the synthesis of?
Definition
adenine and guanine
Term
what is the first enzyme that acts on 6-mercaptpurine when it enters the cell?
Definition
HGPRT - very imp bc can be up/downregulated very quickly
Term
what is an important drug interaction with 6-mercaptopurine?
Definition
allopurinol -used for gout/hyperuricemia
Term
Fludarabine is a ________ analogue
Definition
purine nucleoside
Term
what are the side effects of Fludarabine?
Definition
**TUMOR LYSIS SYNDROME
myelosuppression, nausea, vomiting
Term
Name 3 purine antagonists
Definition
6-mercaptopurine
6-thioguanine
fludarabine
Term
what is tumor lysis syndrome?
Definition
*side effect of fludarabine
hyper - kalemia, uricemia, phosphatemia
hypo - calcemia
results in acute renal failure
Term
what is the mechanism of 5-fluorouracil?
Definition
pyrimidine analog that inhibits thymidylate synthetase, thus preventing synthesis of thymidylic acid needed for DNA synthesis
Term
what is the cause of resistance to 5-fluorouracil?
Definition
altered/increased thymidylate synthase
Term
what is the clinical use of 5-fluorouracil?
Definition
1)leukemia
2)***solid tumors such as breast, GI, ovary, bladder - even whhen alot of cells not in the S phase
Term
what is the mechanism of Capecitabine?
Definition
hydrolyzed to 5-FU by thymidine phosphorylase which is concentrated in tumor cells
Term
In what phase of the cell cycle are cytidine analogs such as Ara-C most toxic?
Definition
S phase
Term
what is the mechanism of Ara-C, cytidine analog?
Definition
terminatees DNA chain elongation - only works in the S phase
Term
what is the clincal use of Ara-C, cytidine analogs?
Definition
acute myelogenous leukemia
**single most effective agent for induction of remission in AML
Term
what is the mechanism of Gemcitabine, cytidine analog?
Definition
terminates DNA chain elongation and inhibits ribonucleotide reductase
**toxicity NOT confined to S phase!!
Term
when is Gemcitabine contraindicated?
Definition
should NOT be used with radiotherapy - it sensitizes all your cells to radiotherapy so cells get damaged that normally wouldn't
Term
Name 4 pyrimidine antagonists
Definition
5-FU
capectibine
cytarabine (C-Ara)
gemcitabine
Term
where does Mitomycin C come from?
Definition
Streptococcus caespitosus
Term
what is the mechanism of Mitomycin C?
Definition
undergoes metabolic activation t become an alkylating agent that cross-links DNA
Term
what type of tumors does Mitomycin C work best in and why?
Definition
**hypoxic tumors due to the chemical necessity for reduction to its active metabolite - important bc core of tumors is usually a hypoxic environment
Term
what are the side effects of Mitomycin C?
Definition
**Hemolytic Uremic Syndrome due to damage to endothelium
Term
what phases of the cell cycle are most sensitive to Etoposide?
Definition
S and G2
Term
what is the mechanim of Etoposide?
Definition
**forms a ternary complex with topoisomerase II**and DNA to prevent resealing of the break that normally follows topoisomerase binding to DNA
Term
what is a side effect seen in patients that were treated with Etoposide for childhood ALL?
Definition
increased incidence of acute nonlymphcytic leukemia
Term
what is the clinical use of Etoposide?
Definition
**Kaposi's sarcoma**
tesicular tumor
small cell carinoma of lung
Term
what is Camptothecin?
Definition
it is a natural product that inhibits topoisomerase I and is S-phase specific
Term
what is the mechanism of Topotecan?
Definition
inhibits topoisomerase I - leads to accumulation of single-stranded breaks
Term
what is a side effect of Topotecan?
Definition
neutropenia
Term
what results in resistance to Topotecan?
Definition
1)decreased intracellular accumulation
2)P-glycoprotein
3)decreased expression or mutation of topoisomerase I
4)exposure to topoisomerase-I inhibitors leads to increased expression of topoisomerase II
Term
what is the current treatment of choice for colorectal cancer?
Definition
Irinotecan
Term
what is the active metabolite of Irinotecan?
Definition
Irinotecan is a prodrug - must be metabolized into **SN-38
Term
what is the mechanism of Irinotecan?
Definition
inhibits topoisomerase I
Term
How is Irinotecan cleared?
Definition
1)**carboxylesterases in the liver
2)**hepatic metabolism via CYP3A
Term
what are the side effects of Irinotecan?
Definition
neutropenia
Term
what is NOT repsonsible for resistance to Irinotecan that causes resistance in Topotecan?
Definition
P-glycoprotein
Term
Tamoxifen is used to treat what type of breats cancer?
Definition
estrogen receptor positive
Term
prostatic carcinoma is dependent on stimulation with _________
Definition
androgens
Term
what type of therpy is used for advanced prostae cancer?
Definition
anti-androgenic
Term
what three hormones are used to treat prostate cancer?
Definition
Leuprolide
Goserelin
Flutamide
Term
what is the mechanism of Leuprolide and Goserelin?
Definition
GnRH agonists that result in initial surge of LH/FSH but then cause the inihibiton of gonadotropin release causing testosterone production to decrease to castration levels
Term
when is Leuprolide and Goserelin use contraindicated?
Definition
during pregnancy - can stimulate abortion
Term
Flutamide has less ________________ than steroid blockers
Definition
loss of libido
Term
what are the side effects of Flutamide?
Definition
**severe liver damage*
gynecomastia, weightt loss, loss of muscle mass, vasomotor flushing
Term
what is Flutamide used to treat?
Definition
prostate cancer
Term
what two drugs are often given together for prostate cancer?
Definition
Flutamide and Leuprolide
Term
what phases of the cell cycle are most vulnerable to Cisplatin/Carboplatin?
Definition
G1 and S
Term
what is the mechanism of Cisplatin/ Carbaplatin?
Definition
bind N7 guanine and form inter and intrastrand cross-links
*inhibit DNA rep. and RNA synthesis
Term
what does L-asparginase inhibit
Definition
protein synthesis
Term
what are the side effects of Cisplatin?
Definition
nephrotoxicity, ototoxicity, and neurotoxicity
Term
what side effects are NOT seen with Carboplastin that are seen when taking Cisplatin?
Definition
nephro- neuro- and ototoxicity
Term
What makes cells resistant to Cisplatin and Carboplatin?
Definition
increased levels of metallothionein which bind to and inactivate both drugs
Term
what can help ameliorate nephrotoxicity when taking Cisplatin?
Definition
aggressive hydration and diuresis
Term
what is the mechanism of hydroxyurea?
Definition
inhibits ribonucleoside diphosphate reductase which catalyzes the reduction conversion of ribonucleotides to deoxyribonucleotides
Term
what phase of the cell cycle is hydroxyurea specific for?
Definition
S phase
Term
what is the clincal use of hydroxyurea?
Definition
1)It potentiates the activity of other DNA damaging drugs such as cisplatin, alkylating agents, topo-II inhibitors and facilitates incoporation of drugs sucha as Ara-C, gemcitabine or fludarabine into DNA
2) it has been placed into several treatment schedules because of its ability to synchronize cells in the radiosensitive portion of the cell cycle
Term
what is the mechansim of action of L-asparaginase?
Definition
catalyzes the deamination of asparagine to aspartic acid and amonia

***some neoplastic cells require an external source of asparagine and this drug metabolizes blood asparagine thus limiting availability for tumor cells
Term
what is the mechanism of Imatinib?
Definition
tyrosine kinase inhibitor
Term
Imatinib is inhibitory against ________ in CML
Definition
BCR-ABL fusion protein
Term
what is Imatinib used to treat?
Definition
CML
Term
what are the side effects of L-asparaginase?
Definition
1)hypersensitivity reactions because it is a foreign protein (derived from bacteria)
2)coma due to ammonia toxicity
Term
what is the mechanism of Gefinitib?
Definition
inhibits EGFR tyrosine kinase - arrests cells at G0/G1
Term
what is the predominate problem for resistance seen to Gefinitib?
Definition
*low response rate* - poor tumor penetration, drug efflux, mutations affecting drug sensitivity
Term
what is the clincal use of Gefinitib?
Definition
non small cell lung cancer in patients that failed standard therapy
Term
High expression of EGFR (epidermal growth factor receptor) is generally associated with ?
Definition
a poor outcome (i.e. invasion, metastasis, late-stage disease, chemo resistance, hormone-therapy resistance)
Term
Gefinitib is a __________ inhibitor.
Definition
EGFR
Term
what is the mechanism of Bevacizumab?
Definition
antiangiogenic - humanized monoclonal antibody against VEGF that prevents interaction with its receptors
Term
what is the clinical use of Bevacizumab?
Definition
colorectal cancer (along with 5-FU)
Term
what are the side effects of Bevacizumab?
Definition
hemorrhage, GI perforation
**severe hypertension, proteinuria, CHF**
Term
what is the clincal use of Thalidomide?
Definition
multiple myeloma
Term
what are the possible mechanisms of Thalidomide?
Definition
(1)inhibition of NFκB or Bcl-2 family members -promoting apoptosis
(2) inhibition of cytokine production -antiangiogenic
(3) immunomodulatory effects
Term
In tumor vascular development, angiogenesis is 3 stages
Definition
1)Initiation
2)proliferation
3)migration and invasion
Term
Name three anti-angiongenic drugs
Definition
1)Bevacizumab
2)Thalidomide
3)Sunitinib
Term
Sunitinib inhibits what two receptors?
Definition
1) VEGF-R
2) PDGF-R
Term
Sunitinib inhibits what two receptors?
Definition
1) VEGF-R
2) PDGF-R
Term
what is the mechanism of action of cyclosporine?
Definition
*binds cyclophilin* - forms a complex that binds calcineurin
Term
What is the primary result of cyclosporine use?
Definition
fewer T lymphocytes
Term
what is the primary result of cyclosporine?
Definition
fewer T lymphocytes
Term
What are the side effects of cyclosporine?
Definition
nephrotoxicity
Term
what are the four categories of immunosuppressives?
Definition
1)glucocorticoids
2)calcineurin inhibitors
3)antiproliferative/antimetabolic agents
4)biologics
Term
Inhibition of CYP 3A by _____________ has a big effect on cyclosporine levels in the body.
Definition
grapefruit juice
Term
What is the main clinical use of cyclosporine?
Definition
1)mainly organ transplantation including: kidney, liver, heart
2)rheumatoid arthritis
3)psoriasis
Term
what is the mechanism os Tacrolimus?
Definition
binds to the immmunophilin, FKBP-12 and inhibits calcineurin
Term
what are the side effects of Tacrolimus?
Definition
**diabetes
nephro and neurotoxicity
Term
What is the mechanism of action of azathioprine?
Definition
It is a prodrug that is converted to 6-MP so it acts as a purine antagonist
Term
what is the clinical use of Tacrolimus?
Definition
used as rescue therapy in patients with rejection episodes despite therapeutic levels of cyclosporine
Term
Azathiopurine is best used for what kind of immune response?
Definition
it is most useful for an acute immune response and has little effect on chronic immune responses
Term
Name two calcineurin inhibitors
Definition
Tacrolimus
Cyclosporine
Term
Azathioprine actually works better than 6-MP which may reflect ____________________.
Definition
better drug uptake or pharmacokinetic profile
Term
Azathiopurine interacts with what other drug?
Definition
allopurinol
Term
what is the effect of GM-CSF?
Definition
stimulates myelopoiesis - produced naturally by endothelial cells, macs, and Tcells
Term
what is the effect of G-CSF?
Definition
increased neutrophil production and enhanced their phagocytic function
Term
what is the treatment of choice for iron deficiency and prophylaxis during pregnancy?
Definition
ORAL iron therapy
Term
what is the mechanism of Deferoxamine?
Definition
chelates excess iron
Term
what is contraindicated in oral iron therapy?
Definition
antacids - prevent absorption
Term
Deficiency of what two things can cause megaloblastic anemia?
Definition
vitamin B12
folic acid
Term
what are the 5 alkylating agents that Bauer described?
Definition
1)mechloraethamine
2)cyclophosphamide
3)melphalan
4)busulfan
5)nitrosureas
Term
Name 3 Purine antagonists:
Definition
1)6-mercaptopurine
2)6-thioguanine
3)fludarabine
Term
What is the mechanism of action of 6-mercaptopurine?
Definition
(structural analog of adenine)It inhibits de novo synthesis of adenine AND guanine
Term
Name the four pyrimidine antagonist:
Definition
1)5-fluorouracil
2)capectibine
3)cytarabine
4)gemcitabine
Term
____________ is necessary for the maturations and proliferation of t-cells.
Definition
IL-2
Term
Name 2 calcineurin inhibitors:
Definition
1)cyclosporine
2)tacrolimus

(by inhibiting calcineurin, they stop production of IL-2 thus stopping maturation and proliferation of T-cells)
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