Toxicology: superwarfarin poisoning: 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: superwarfarin poisoning

Sample item

A girl swallows a rodent bait and presents three days later with bruising, haematuria and an INR above 10. After vitamin K and fresh frozen plasma she improves, but the INR rises again when treatment is stopped. Why does she need vitamin K for weeks?

AThe poison is regenerated in the liver from vitamin KBThe anticoagulant is highly lipid soluble with a very long half-lifeCVitamin K is destroyed within an hour of injectionDThe poison permanently destroys clotting factor genes

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

The answer and the reasoning

B. The anticoagulant is highly lipid soluble with a very long half-life

Long-acting anticoagulant rodenticides such as brodifacoum and bromadiolone are highly lipid soluble and stored in the liver, with half-lives of weeks. They block vitamin K epoxide reductase for a long time, so vitamin K must continue for weeks with INR monitoring. Warfarin, with its short action, needs only days.

Option by option

A. The poison is regenerated in the liver from vitamin K
The poison is not made from vitamin K; it is an inhibitor of vitamin K recycling.
B. The anticoagulant is highly lipid soluble with a very long half-life (correct)
Correct. The persistence of the lipid-soluble agent keeps blocking vitamin K recycling.
C. Vitamin K is destroyed within an hour of injection
Vitamin K has a short action, but the problem is the persistence of the poison.
D. The poison permanently destroys clotting factor genes
Clotting factor genes are not destroyed; synthesis of active factors is blocked.

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.

Questions about this Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is B, The anticoagulant is highly lipid soluble with a very long half-life. Long-acting anticoagulant rodenticides such as brodifacoum and bromadiolone are highly lipid soluble and stored in the liver, with half-lives of weeks.

Why is "The poison is regenerated in the liver from vitamin K" not the answer?

The poison is not made from vitamin K; it is an inhibitor of vitamin K recycling.

Why is "Vitamin K is destroyed within an hour of injection" not the answer?

Vitamin K has a short action, but the problem is the persistence of the poison.

Why is "The poison permanently destroys clotting factor genes" not the answer?

Clotting factor genes are not destroyed; synthesis of active factors is blocked.

What concept does this question test?

It tests Toxicology: superwarfarin poisoning in Forensic Medicine. They block vitamin K epoxide reductase for a long time, so vitamin K must continue for weeks with INR monitoring. Warfarin, with its short action, needs only days.

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: superwarfarin poisoning?

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.