Toxicology and antidotes: muscarine mushroom poisoning: 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 · Toxicology and antidotes: muscarine mushroom poisoning

Sample item

Thirty minutes after eating foraged wild mushrooms, a man has profuse sweating, salivation, lacrimation, miosis, bradycardia and wheeze. There are no fasciculations and no delirium. Which drug is the specific antidote?

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

The answer and the reasoning

D. Atropine

Some Inocybe and Clitocybe species contain muscarine, which directly stimulates muscarinic receptors and gives a purely muscarinic toxidrome of early onset. Atropine blocks these receptors. Pralidoxime has no role because cholinesterase is not inhibited.

Option by option

  • A. Neostigmine

    Neostigmine inhibits cholinesterase and would increase acetylcholine, worsening symptoms.

  • B. Physostigmine

    Physostigmine is a cholinesterase inhibitor and would worsen the cholinergic state.

  • C. Pralidoxime

    Pralidoxime reactivates phosphorylated cholinesterase and is useless when the enzyme is intact.

  • D. Atropine (correct)

    Correct. Atropine competitively blocks the muscarinic receptors stimulated by muscarine.

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 D, Atropine. Some Inocybe and Clitocybe species contain muscarine, which directly stimulates muscarinic receptors and gives a purely muscarinic toxidrome of early onset.

Why is "Neostigmine" not the answer?

Neostigmine inhibits cholinesterase and would increase acetylcholine, worsening symptoms.

Why is "Physostigmine" not the answer?

Physostigmine is a cholinesterase inhibitor and would worsen the cholinergic state.

Why is "Pralidoxime" not the answer?

Pralidoxime reactivates phosphorylated cholinesterase and is useless when the enzyme is intact.

What concept does this question test?

It tests Toxicology and antidotes: muscarine mushroom poisoning in Pharmacology. Atropine blocks these receptors. Pralidoxime has no role because cholinesterase is not inhibited.

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 Toxicology and antidotes: muscarine mushroom poisoning?

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.