Antidotes: cobra envenomation: 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 · Antidotes: cobra envenomation

Sample item

A man bitten by a snake that spread a hood has ptosis and descending paralysis, with a normal 20-minute whole blood clotting test. Neurological signs persist after polyvalent antivenom. What additional drug treatment may help?

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

The answer and the reasoning

D. Neostigmine with atropine

Cobra venom contains postsynaptic neurotoxins that compete with acetylcholine at the nicotinic receptor, and an acetylcholinesterase inhibitor can raise acetylcholine and partly reverse the block. Atropine is given first to prevent muscarinic effects, and the response is tested with a trial dose. Krait neurotoxins act presynaptically and respond poorly.

Option by option

  • A. Dantrolene

    Dantrolene treats malignant hyperthermia and has no role in envenomation.

  • B. Vitamin K

    Vitamin K corrects coagulopathy, which is absent.

  • C. Fresh frozen plasma

    The clotting test is normal, so plasma replacement is not needed.

  • D. Neostigmine with atropine (correct)

    Neostigmine can overcome competitive postsynaptic blockade, with atropine to limit muscarinic effects.

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, Neostigmine with atropine. Cobra venom contains postsynaptic neurotoxins that compete with acetylcholine at the nicotinic receptor, and an acetylcholinesterase inhibitor can raise acetylcholine and partly reverse the block.

Why is "Dantrolene" not the answer?

Dantrolene treats malignant hyperthermia and has no role in envenomation.

Why is "Vitamin K" not the answer?

Vitamin K corrects coagulopathy, which is absent.

Why is "Fresh frozen plasma" not the answer?

The clotting test is normal, so plasma replacement is not needed.

What concept does this question test?

It tests Antidotes: cobra envenomation in Pharmacology. Atropine is given first to prevent muscarinic effects, and the response is tested with a trial dose. Krait neurotoxins act presynaptically and respond poorly.

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 Antidotes: cobra envenomation?

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.