Pharmacogenetics: 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 · Pharmacogenetics

Sample item

Why can codeine have variable analgesic effect between patients?

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

The answer and the reasoning

B. CYP2D6 metabolism to morphine varies

Codeine requires CYP2D6 conversion to morphine, so poor metabolizers may have little effect while ultrarapid metabolizers may have toxicity.

Option by option

  • A. All patients form identical morphine levels

    Metabolism varies substantially between people.

  • B. CYP2D6 metabolism to morphine varies (correct)

    Correct: CYP2D6 variation changes active metabolite exposure.

  • C. It acts only on peripheral receptors

    Central opioid receptors mediate analgesia.

  • D. It is not absorbed orally

    Codeine is orally absorbed.

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, CYP2D6 metabolism to morphine varies. Codeine requires CYP2D6 conversion to morphine, so poor metabolizers may have little effect while ultrarapid metabolizers may have toxicity.

Why is "All patients form identical morphine levels" not the answer?

Metabolism varies substantially between people.

Why is "It acts only on peripheral receptors" not the answer?

Central opioid receptors mediate analgesia.

Why is "It is not absorbed orally" not the answer?

Codeine is orally absorbed.

What concept does this question test?

It tests Pharmacogenetics in Pharmacology. The correct option holds because: Correct: CYP2D6 variation changes active metabolite exposure.

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 Pharmacogenetics?

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.