Intravenous and inhalational agents: transdermal fentanyl and fever: 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 · Intravenous and inhalational agents: transdermal fentanyl and fever

Sample item

A man using a transdermal fentanyl patch for cancer pain develops a fever of 39.5 degrees C and becomes drowsy with slow respiration. What is the explanation?

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

The answer and the reasoning

A. Fever increases absorption of fentanyl from the patch

Heat and fever increase skin blood flow and the rate of fentanyl absorption from the patch, so plasma levels rise and toxicity can occur. Patients are advised to avoid heat pads, and the patch is removed if toxicity is suspected, with naloxone as needed.

Option by option

  • A. Fever increases absorption of fentanyl from the patch (correct)

    Correct. Warmer skin and increased blood flow raise absorption.

  • B. Fever releases fentanyl stored in muscle

    Fentanyl is not stored in muscle and released by fever.

  • C. Fever converts fentanyl to an active metabolite

    Fentanyl is metabolised to inactive norfentanyl.

  • D. Fever decreases hepatic metabolism of morphine metabolites

    The patient is on fentanyl, not morphine.

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 A, Fever increases absorption of fentanyl from the patch. Heat and fever increase skin blood flow and the rate of fentanyl absorption from the patch, so plasma levels rise and toxicity can occur.

Why is "Fever releases fentanyl stored in muscle" not the answer?

Fentanyl is not stored in muscle and released by fever.

Why is "Fever converts fentanyl to an active metabolite" not the answer?

Fentanyl is metabolised to inactive norfentanyl.

Why is "Fever decreases hepatic metabolism of morphine metabolites" not the answer?

The patient is on fentanyl, not morphine.

What concept does this question test?

It tests Intravenous and inhalational agents: transdermal fentanyl and fever in Anaesthesia. Patients are advised to avoid heat pads, and the patch is removed if toxicity is suspected, with naloxone as 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 Intravenous and inhalational agents: transdermal fentanyl and fever?

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.