Toxicology: cantharidin: 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: cantharidin

Sample item

A man takes a powder sold as an aphrodisiac made from a dried beetle. He develops a burning mouth, vomiting, blood in the urine with painful straining to pass urine, and persistent painful erection. Which poison is responsible?

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

The answer and the reasoning

C. Cantharidin

Cantharidin comes from the blister beetle (Spanish fly) and is a vesicant that irritates the gut and urinary tract, causing haematuria, strangury and priapism. It is abused as an aphrodisiac. Toxicity can cause renal failure, and treatment is supportive.

Option by option

  • A. Datura alkaloids

    Datura alkaloids cause an anticholinergic syndrome with urinary retention.

  • B. Ergotamine

    Ergotamine causes vasospasm and gangrene and is not derived from a beetle.

  • C. Cantharidin (correct)

    Correct. Beetle-derived cantharidin explains the urinary irritation and priapism.

  • D. Strychnine

    Strychnine causes convulsions with a clear sensorium and not urinary irritation.

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 C, Cantharidin. Cantharidin comes from the blister beetle (Spanish fly) and is a vesicant that irritates the gut and urinary tract, causing haematuria, strangury and priapism.

Why is "Datura alkaloids" not the answer?

Datura alkaloids cause an anticholinergic syndrome with urinary retention.

Why is "Ergotamine" not the answer?

Ergotamine causes vasospasm and gangrene and is not derived from a beetle.

Why is "Strychnine" not the answer?

Strychnine causes convulsions with a clear sensorium and not urinary irritation.

What concept does this question test?

It tests Toxicology: cantharidin in Forensic Medicine. It is abused as an aphrodisiac. Toxicity can cause renal failure, and treatment is supportive.

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: cantharidin?

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.