Anticancer drugs: toxicity prevention: practice question

A Pharmacology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pharmacology · Anticancer drugs: toxicity prevention

Sample item

A patient receiving high-dose cyclophosphamide develops haematuria. Which drug is given to prevent this complication, and how does it work?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Mesna, which binds the urotoxic metabolite acrolein in the bladder

Cyclophosphamide is metabolised to acrolein, which damages the bladder urothelium and causes haemorrhagic cystitis. Mesna is excreted in urine and neutralises acrolein by its sulfhydryl group. Hydration also helps. Ifosfamide has the same risk.

Option by option

  • A. Leucovorin, which bypasses dihydrofolate reductase

    Leucovorin rescues cells from methotrexate toxicity.

  • B. Mesna, which binds the urotoxic metabolite acrolein in the bladder (correct)

    Correct. Mesna's thiol group binds acrolein in the urine.

  • C. Dexrazoxane, which chelates iron

    Dexrazoxane reduces doxorubicin cardiotoxicity.

  • D. Amifostine, which chelates platinum

    Amifostine is a cytoprotective agent used with cisplatin for renal and other toxicity, not for cystitis.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Pharmacology questions

Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is B, Mesna, which binds the urotoxic metabolite acrolein in the bladder. Cyclophosphamide is metabolised to acrolein, which damages the bladder urothelium and causes haemorrhagic cystitis.

Why is "Leucovorin, which bypasses dihydrofolate reductase" not the answer?

Leucovorin rescues cells from methotrexate toxicity.

Why is "Dexrazoxane, which chelates iron" not the answer?

Dexrazoxane reduces doxorubicin cardiotoxicity.

Why is "Amifostine, which chelates platinum" not the answer?

Amifostine is a cytoprotective agent used with cisplatin for renal and other toxicity, not for cystitis.

What concept does this question test?

It tests Anticancer drugs: toxicity prevention in Pharmacology. Mesna is excreted in urine and neutralises acrolein by its sulfhydryl group. Hydration also helps. Ifosfamide has the same risk.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Anticancer drugs: toxicity prevention?

Learn drugs as classes, then the exception in each class that an examiner would pick. Then use the flashcards and the other Pharmacology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.