A. Dihydrofolate reductase inhibitor
B. Inhibition of purine ring
C. Inhibit dTMP biosynthesis
D. A & B
E. All of the above
Answer: E. All of the above
Methotrexate: Small amount of MTX undergo hydroxylation at the 7th position to form 7-hydroxymethotrexate which is less water soluble than MTX and lead to crystalluria. That's why patients should be well hydrated to avoid renal toxicity.
02. Mechanism of action of 5-Fluorouracil?
A. Dihydrofolate reductase inhibitor
B. Inhibit dTMP synthesis
C. Terminate DNA chain elongation
D. Scission of DNA by oxidation
E. Disrupts DNA function
Answer: B. Inhibit dTMP synthesis
Needed for DNA synthesis
High level of dihydropyrimidine dehydrogenase DPD can increase the rate of 5FU catabolism leading to decrease in bioavailability.
Low levels of DPD causes severe toxicity like diarrhoea, pancytopenia, mucositis.
Same like Flucytosine antimetabolite antifungal drug.
03. Mechanism of action of Cytarabine?
A. Dihydrofolate reductase inhibitor
B. Inhibit dTMP synthesis
C. Terminate DNA chain elongation
D. Scission of DNA by oxidation
E. Disrupts DNA function
Answer: C. Terminate DNA chain elongation
04. Mechanism of action of Bleomycin?
A. A. Dihydrofolate reductase inhibitor
B. Inhibit dTMP synthesis
C. Terminate DNA chain elongation
D. Scission of DNA by oxidation
E. Disrupts DNA function
Answer: D. Scission of DNA by oxidation
05. Mechanism of action of Dactinomycin?
A. A. Dihydrofolate reductase inhibitor
B. Inhibit dTMP synthesis
C. Terminate DNA chain elongation
D. Scission of DNA by oxidation
E. Disrupts DNA function
Answer: E. Disrupts DNA function
06. Mechanism of action of Leucovorin?
A. A. Dihydrofolate reductase inhibitor
B. Inhibit dTMP synthesis
C. Terminate DNA chain elongation
D. Scission of DNA by oxidation
E. Reverse inhibition of dihydrofolate reductase
Answer: E. Reverse inhibition of dihydrofolate reductase
07. Which of the following statements about Methotrexate is wrong?
A. Anti folate agent
B. Specific for S phase
C. Inhibit thymidylate synthase
D. Low dose for psoriasis
E. Pemetrexed antidote to methotrexate
Answer: E. Pemetrexed antidote to methotrexate
Pemetrexed and Pralatrexate are also anti metabolites that inhibit DHFR.
Pemetrexed is used for non small cell lung
Pralatrexate is used in relapsed or refractory T-cell lymphoma
08. Methotrexate in combination is affective against following?
A. Acute lymphocytic leukaemia
B. Burkitt Lymphoma
C. Breast cancer
D. Bladder cancer
E. Head and neck carcinoma
F. All of the above
Answer: F. All of the above
09. Methotrexate doesn't easily penetrate the blood brain barrier, following route used to destroy neoplastic cells in sanctuary of CNS?
A. Intravenous
B. Intrathecally
C. Intramuscular
D. Sublingual
E. Subcutaneous
Answer: B. Intrathecally
10. Pralatrexate and Pemetrexed should be given with following to reduce hematologic and GI toxicity?
A. Cladribine
B. Cisplatin
C. Folic acid
D. Cytarabine
E. Azacitidine
Answer: C. Folic acid
11. Following drug is administered IV rather than orally because intestinal bacteria split off the sugar to yield the very toxic metabolite, fluoroadenine?
A. 5-Fluorouracil
B. Fludarabine
C. Azacitidine
D. 6-Mercaptopurine
Answer: B. Fludarabine
12. Which of the following statements about 5-Fluorouracil is wrong?
A. Pyrimidine Analog
B. Stable fluorine atom at position 5 or uracil ring
C. Fluorine interrupt conversion of deoxyuridylic acid to thymidylic acid
D. Used in slow growing solid tumor
E. Not effective for superficial basal cell carcinoma
Answer: E. Not effective for superficial basal cell carcinoma
Fluorine interrupt conversion of deoxyuridylic acid to thymidylic acid, this leads to lack the cell of thymidine which is an essential precursor for DNA synthesis.
13. Thymidine less death of rapidly dividing cells caused by?
A. Gemcitabine
B. Azacitidine
C. Capecitabine
D. 5-Fluorouracil
E. Cytarabine
Answer: D. 5-Fluorouracil
5-FC enter the cell and converted to the deoxynucleotide(5-fluoro-deoxyuridine mono phosphate 5-FdUMP. Which competes with deoxyuridine mono phosphate for thymidylate synthase thus inhibiting it's action.
14. Inhibition of thymidylate synthase by 5-Fluorouracil causes reduced folate coenzyme, to prevent this folate reduction we use?
A. Methotrexate
B. Leucovorin
C. Capecitabine
D. Azacitidine
E. Gemcitabine
Answer: B. Leucovorin
15. Body surface area (BSA) is used in calculating chemotherapy doses because?
(A) BSA is anindicator of tumor cell mass.
(B) BSA correlates with cardiac output.
(C) BSA correlates with gastrointestinal transit
time.
(D) the National Cancer Institute requires that BSA
be used.
(E) the U.S. Food and Drug Administration (FDA) requires that BSA be used.
Answer: (B) BSA correlates with cardiac output.
16. The rationale for combination chemotherapy includes all of the following except
(A) biochemical enhancement of effect.
(B) rescue of normal cells.
(C) overcoming or preventing resistance.
(D) biochemical nullification of effect.
(E) cytotoxic to both resting and dividing cells.
Answer: D) biochemical nullification of effect.
17. All of the following chemotherapy agents can be administered intrathecally except
(A) methotrexate.
(B) cytarabine.
(C) hydrocortisone.
(D) thiotepa.
(E) vincristine.
Answer: E) vincristine.
18. Hypersensitivity reactions have been commonly associated with all of the following agents except
(A) asparaginase.
(B) busulfan.
(C) carboplatin.
(D) etoposide.
(E) paclitaxel.
Answer: B. Busulfan
19. Which of these supportive agents may have a greater risk than benefit in patients with cancer when the goal is cure due to the potential increased risk of tumor progression?
(A) Antiemetics
(B) Colony-stimulating factors
(C) Corticosteroids
(D) Erythropoietin-stimulating agents
(E) Oprelvekin (IL-11)
Answer: D) Erythropoietin-stimulating agents
20. How do antimetabolites exert their cytotoxic effect?
(A) Inhibiting DNA synthesis by sliding between DNA base pairs
(B) Inhibiting RNA synthesis by sliding between RNA base pairs
(C) Actingasfalsemetabolitesinthemicrotubules
(D) Acting as false substitutions in the production of
nucleic acids
(E) Promoting microtubule assembly and
stabilization
Answer: D) Acting as false substitutions in the production of
nucleic acids
21. All of the following chemotherapy agents work through affecting microtubule function except
(A) docetaxel.
(B) vinblastine.
(C) mitoxantrone.
(D) vincristine.
(E) vinorelbine.
Answer: A) docetaxel.
22. When does the neutrophil nadir associated with chemotherapy agents generally occur?
(A) During administration of the chemotherapy
(B) 1 to 2 days after therapy
(C) 10 to14 days after therapy
(D) 1 month after therapy
(E) When the platelet count begins to rise
Answer: C) 10 to14 days after therapy
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