Opioids: remifentanil: practice question

A Anaesthesia 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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Anaesthesia · Opioids: remifentanil

Sample item

Why does remifentanil have a context-sensitive half-time of about 3 to 4 minutes regardless of infusion duration?

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

The answer and the reasoning

D. It is metabolised by non-specific plasma and tissue esterases

Remifentanil is an ester hydrolysed rapidly by non-specific blood and tissue esterases, not by plasma cholinesterase. Offset is therefore fast, so postoperative analgesia must be planned before stopping the infusion.

Option by option

  • A. It is excreted unchanged by the kidneys

    Renal excretion of unchanged drug is not the main route.

  • B. It is metabolised by hepatic CYP3A4

    CYP3A4 metabolism applies to fentanyl and alfentanil.

  • C. It is redistributed to fat only

    Fat redistribution does not explain the constant offset.

  • D. It is metabolised by non-specific plasma and tissue esterases (correct)

    Correct. Esterase hydrolysis gives a constant short half-time.

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 Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is D, It is metabolised by non-specific plasma and tissue esterases. Remifentanil is an ester hydrolysed rapidly by non-specific blood and tissue esterases, not by plasma cholinesterase.

Why is "It is excreted unchanged by the kidneys" not the answer?

Renal excretion of unchanged drug is not the main route.

Why is "It is metabolised by hepatic CYP3A4" not the answer?

CYP3A4 metabolism applies to fentanyl and alfentanil.

Why is "It is redistributed to fat only" not the answer?

Fat redistribution does not explain the constant offset.

What concept does this question test?

It tests Opioids: remifentanil in Anaesthesia. Offset is therefore fast, so postoperative analgesia must be planned before stopping the infusion.

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 Opioids: remifentanil?

Make a table of each agent, its key advantage and its main side effect. Then use the flashcards and the other Anaesthesia 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.