Autonomic pharmacology: 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 · Autonomic pharmacology

Sample item

A young man who ate datura seeds is agitated and delirious, with hot dry flushed skin, dilated pupils and tachycardia. Which drug can reverse both central and peripheral features?

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

The answer and the reasoning

D. Physostigmine

Datura contains atropine-like antimuscarinic alkaloids. Physostigmine is a tertiary amine that crosses the blood-brain barrier and so reverses central as well as peripheral anticholinergic effects.

Option by option

  • A. Neostigmine

    Neostigmine is a quaternary compound that does not enter the CNS, so delirium would persist.

  • B. Pyridostigmine

    Pyridostigmine is also quaternary and acts mainly peripherally, used for myasthenia gravis.

  • C. Edrophonium

    Edrophonium is a short-acting quaternary agent used for diagnostic testing and does not enter the brain.

  • D. Physostigmine (correct)

    Correct. As a tertiary amine it enters the brain and reverses both central and peripheral toxicity.

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, Physostigmine. Datura contains atropine-like antimuscarinic alkaloids.

Why is "Neostigmine" not the answer?

Neostigmine is a quaternary compound that does not enter the CNS, so delirium would persist.

Why is "Pyridostigmine" not the answer?

Pyridostigmine is also quaternary and acts mainly peripherally, used for myasthenia gravis.

Why is "Edrophonium" not the answer?

Edrophonium is a short-acting quaternary agent used for diagnostic testing and does not enter the brain.

What concept does this question test?

It tests Autonomic pharmacology in Pharmacology. Physostigmine is a tertiary amine that crosses the blood-brain barrier and so reverses central as well as peripheral anticholinergic effects.

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 Autonomic pharmacology?

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.