Toxicology: naloxone resedation: practice question

A Forensic Medicine 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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Forensic Medicine · Toxicology: naloxone resedation

Sample item

A heroin user is revived with intravenous naloxone but refuses admission. About 90 minutes later he is found drowsy with slow breathing. Why has this happened?

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

The answer and the reasoning

A. Naloxone acts for a shorter time than many opioids

Naloxone is a competitive antagonist with a duration of about 30 to 90 minutes, shorter than the effect of many opioids. Once it wears off, the unreversed opioid again depresses respiration. Patients should be observed, and repeated doses or an infusion may be needed.

Option by option

  • A. Naloxone acts for a shorter time than many opioids (correct)

    Correct. Naloxone wears off before the opioid does, so sedation and apnoea return.

  • B. Heroin is stored as a depot that releases it slowly

    Heroin has no depot effect from which release follows a delay.

  • C. Opioid receptors were permanently damaged by heroin

    Heroin does not cause permanent receptor damage.

  • D. Naloxone causes rebound respiratory depression

    Naloxone does not itself depress respiration.

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 Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is A, Naloxone acts for a shorter time than many opioids. Naloxone is a competitive antagonist with a duration of about 30 to 90 minutes, shorter than the effect of many opioids.

Why is "Heroin is stored as a depot that releases it slowly" not the answer?

Heroin has no depot effect from which release follows a delay.

Why is "Opioid receptors were permanently damaged by heroin" not the answer?

Heroin does not cause permanent receptor damage.

Why is "Naloxone causes rebound respiratory depression" not the answer?

Naloxone does not itself depress respiration.

What concept does this question test?

It tests Toxicology: naloxone resedation in Forensic Medicine. Once it wears off, the unreversed opioid again depresses respiration. Patients should be observed, and repeated doses or an infusion may be needed.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Toxicology: naloxone resedation?

Learn postmortem changes with their timelines, and toxicology as poison, sign, test and antidote. Then use the flashcards and the other Forensic Medicine 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.