,NURS 6521 Week 9 Quiz | Advanced Pharmacology (2026) Q&A |
Walden University
1. Which of the following best describes the primary mechanism of action of
methotrexate?
A) Inhibiting dihydrofolate reductase and blocking DNA synthesis
B) Inhibiting thymidylate synthase and blocking pyrimidine synthesis
C) Inhibiting topoisomerase I and causing DNA strand breaks
D) Inhibiting microtubule polymerization and blocking mitosis
Correct Answer: Inhibiting dihydrofolate reductase and blocking DNA synthesis
Rationale: Methotrexate inhibits dihydrofolate reductase, reducing tetrahydrofolate and
impairing DNA synthesis in rapidly dividing cells. It is used for cancer, rheumatoid arthritis,
and ectopic pregnancy. Leucovorin is the rescue agent for toxicity. It does not primarily
inhibit thymidylate synthase, topoisomerase I, or microtubules.
2. What is the recommended antidote for methotrexate toxicity?
A) Protamine sulfate
B) Leucovorin
C) Naloxone
D) Flumazenil
Correct Answer: Leucovorin
,Rationale: Leucovorin is a reduced form of folate that bypasses the blocked dihydrofolate
reductase step, rescuing normal cells from methotrexate toxicity. It is administered after
high-dose methotrexate therapy. Protamine reverses heparin, naloxone reverses opioids,
and flumazenil reverses benzodiazepines.
3. Which chemotherapeutic agent is most associated with hemorrhagic cystitis?
A) Doxorubicin
B) Bleomycin
C) Cyclophosphamide
D) Vincristine
Correct Answer: Cyclophosphamide
Rationale: Cyclophosphamide can cause hemorrhagic cystitis due to acrolein, a toxic
metabolite excreted in urine. Hydration and mesna are used to prevent this complication.
Doxorubicin causes cardiotoxicity, bleomycin causes pulmonary fibrosis, and vincristine
causes peripheral neuropathy.
4. What drug is administered to prevent hemorrhagic cystitis from ifosfamide?
A) Dexrazoxane
B) Leucovorin
C) Mesna
D) Amifostine
Correct Answer: Mesna
, Rationale: Mesna binds acrolein in the urine, preventing its toxic effects on the bladder
mucosa. It is used with ifosfamide and cyclophosphamide. Dexrazoxane reduces
anthracycline cardiotoxicity, leucovorin rescues methotrexate toxicity, and amifostine
protects against radiation and cisplatin toxicity.
5. Cardiotoxicity is a major dose-limiting adverse effect of which anthracycline?
A) Doxorubicin
B) Bleomycin
C) Vincristine
D) Etoposide
Correct Answer: Doxorubicin
Rationale: Doxorubicin causes cumulative, dose-dependent cardiotoxicity due to free
radical formation and oxidative damage to cardiac myocytes. Dexrazoxane is used as a
cardioprotectant. Bleomycin causes pulmonary fibrosis, vincristine causes neuropathy, and
etoposide causes myelosuppression.
6. Which agent is used to reduce doxorubicin-induced cardiotoxicity?
A) Mesna
B) Dexrazoxane
C) Leucovorin
D) Amifostine
Correct Answer: Dexrazoxane
Walden University
1. Which of the following best describes the primary mechanism of action of
methotrexate?
A) Inhibiting dihydrofolate reductase and blocking DNA synthesis
B) Inhibiting thymidylate synthase and blocking pyrimidine synthesis
C) Inhibiting topoisomerase I and causing DNA strand breaks
D) Inhibiting microtubule polymerization and blocking mitosis
Correct Answer: Inhibiting dihydrofolate reductase and blocking DNA synthesis
Rationale: Methotrexate inhibits dihydrofolate reductase, reducing tetrahydrofolate and
impairing DNA synthesis in rapidly dividing cells. It is used for cancer, rheumatoid arthritis,
and ectopic pregnancy. Leucovorin is the rescue agent for toxicity. It does not primarily
inhibit thymidylate synthase, topoisomerase I, or microtubules.
2. What is the recommended antidote for methotrexate toxicity?
A) Protamine sulfate
B) Leucovorin
C) Naloxone
D) Flumazenil
Correct Answer: Leucovorin
,Rationale: Leucovorin is a reduced form of folate that bypasses the blocked dihydrofolate
reductase step, rescuing normal cells from methotrexate toxicity. It is administered after
high-dose methotrexate therapy. Protamine reverses heparin, naloxone reverses opioids,
and flumazenil reverses benzodiazepines.
3. Which chemotherapeutic agent is most associated with hemorrhagic cystitis?
A) Doxorubicin
B) Bleomycin
C) Cyclophosphamide
D) Vincristine
Correct Answer: Cyclophosphamide
Rationale: Cyclophosphamide can cause hemorrhagic cystitis due to acrolein, a toxic
metabolite excreted in urine. Hydration and mesna are used to prevent this complication.
Doxorubicin causes cardiotoxicity, bleomycin causes pulmonary fibrosis, and vincristine
causes peripheral neuropathy.
4. What drug is administered to prevent hemorrhagic cystitis from ifosfamide?
A) Dexrazoxane
B) Leucovorin
C) Mesna
D) Amifostine
Correct Answer: Mesna
, Rationale: Mesna binds acrolein in the urine, preventing its toxic effects on the bladder
mucosa. It is used with ifosfamide and cyclophosphamide. Dexrazoxane reduces
anthracycline cardiotoxicity, leucovorin rescues methotrexate toxicity, and amifostine
protects against radiation and cisplatin toxicity.
5. Cardiotoxicity is a major dose-limiting adverse effect of which anthracycline?
A) Doxorubicin
B) Bleomycin
C) Vincristine
D) Etoposide
Correct Answer: Doxorubicin
Rationale: Doxorubicin causes cumulative, dose-dependent cardiotoxicity due to free
radical formation and oxidative damage to cardiac myocytes. Dexrazoxane is used as a
cardioprotectant. Bleomycin causes pulmonary fibrosis, vincristine causes neuropathy, and
etoposide causes myelosuppression.
6. Which agent is used to reduce doxorubicin-induced cardiotoxicity?
A) Mesna
B) Dexrazoxane
C) Leucovorin
D) Amifostine
Correct Answer: Dexrazoxane
