Toxicology: dimercaprol contraindication: 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: dimercaprol contraindication

Sample item

A factory worker with chronic cadmium poisoning has tubular proteinuria. A junior doctor proposes dimercaprol (BAL). Why should this be avoided?

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

The answer and the reasoning

C. The cadmium-BAL complex is more nephrotoxic than cadmium alone

Dimercaprol is indicated in arsenic, inorganic mercury and gold poisoning. It should not be used for cadmium, iron or selenium, because the complexes formed are more toxic, and cadmium complexes damage the kidney further. Its use is also avoided in G6PD deficiency.

Option by option

  • A. BAL is effective only for lead poisoning

    BAL is used for arsenic and mercury and is not limited to lead.

  • B. BAL is rapidly inactivated by cadmium before it can chelate

    BAL is not inactivated; the problem is the toxicity of the complex.

  • C. The cadmium-BAL complex is more nephrotoxic than cadmium alone (correct)

    Correct. The complex is more toxic to the kidney, so BAL is contraindicated.

  • D. BAL causes severe hypokalaemia in cadmium toxicity

    Hypokalaemia is not the reason for avoiding it.

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, The cadmium-BAL complex is more nephrotoxic than cadmium alone. Dimercaprol is indicated in arsenic, inorganic mercury and gold poisoning.

Why is "BAL is effective only for lead poisoning" not the answer?

BAL is used for arsenic and mercury and is not limited to lead.

Why is "BAL is rapidly inactivated by cadmium before it can chelate" not the answer?

BAL is not inactivated; the problem is the toxicity of the complex.

Why is "BAL causes severe hypokalaemia in cadmium toxicity" not the answer?

Hypokalaemia is not the reason for avoiding it.

What concept does this question test?

It tests Toxicology: dimercaprol contraindication in Forensic Medicine. It should not be used for cadmium, iron or selenium, because the complexes formed are more toxic, and cadmium complexes damage the kidney further. Its use is also avoided in G6PD deficiency.

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: dimercaprol contraindication?

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.