Antiviral drugs: 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 · Antiviral drugs

Sample item

An HIV patient on a zidovudine-containing regimen develops macrocytic anaemia. What is the mechanism of this toxicity?

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

The answer and the reasoning

C. Suppression of erythroid precursors in the bone marrow

Zidovudine is a thymidine analogue that is toxic to marrow progenitors, causing macrocytic anaemia and neutropenia. Dose reduction or switching drugs may be needed.

Option by option

  • A. Vitamin B12 malabsorption in the ileum

    Zidovudine does not impair B12 absorption.

  • B. Oxidant haemolysis in G6PD deficiency

    Oxidant haemolysis requires G6PD deficiency and drugs such as primaquine.

  • C. Suppression of erythroid precursors in the bone marrow (correct)

    Direct marrow suppression with macrocytosis is the typical toxicity.

  • D. Immune haemolysis through hapten formation

    Hapten-mediated immune haemolysis is classically linked to drugs such as penicillin and methyldopa.

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.

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Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is C, Suppression of erythroid precursors in the bone marrow. Zidovudine is a thymidine analogue that is toxic to marrow progenitors, causing macrocytic anaemia and neutropenia.

Why is "Vitamin B12 malabsorption in the ileum" not the answer?

Zidovudine does not impair B12 absorption.

Why is "Oxidant haemolysis in G6PD deficiency" not the answer?

Oxidant haemolysis requires G6PD deficiency and drugs such as primaquine.

Why is "Immune haemolysis through hapten formation" not the answer?

Hapten-mediated immune haemolysis is classically linked to drugs such as penicillin and methyldopa.

What concept does this question test?

It tests Antiviral drugs in Pharmacology. Dose reduction or switching drugs may be needed.

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 Antiviral drugs?

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.