Toxicology and antidotes: isopropyl alcohol poisoning: 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.

Try it

Pharmacology · Toxicology and antidotes: isopropyl alcohol poisoning

Sample item

A man found drowsy with a fruity odour on his breath has normal blood glucose and strongly positive serum ketones. Arterial pH is 7.38 with normal bicarbonate, the osmolar gap is raised, and he has no visual symptoms. Which ingestion is most likely?

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

The answer and the reasoning

C. Isopropyl alcohol

Isopropyl alcohol is metabolised by alcohol dehydrogenase to acetone, which causes ketosis without significant acidosis, and the parent alcohol raises the osmolar gap. Methanol and ethylene glycol produce a high anion gap metabolic acidosis, with visual loss or crystalluria respectively.

Option by option

  • A. Methanol

    Methanol produces formic acid, severe anion gap acidosis and visual loss.

  • B. Ethylene glycol

    Ethylene glycol produces oxalic acid, acidosis, hypocalcaemia and renal failure.

  • C. Isopropyl alcohol (correct)

    Correct. Ketosis without acidosis with an osmolar gap points to isopropyl alcohol.

  • D. Propylene glycol

    Propylene glycol causes lactic acidosis, and acetone ketosis is not a feature.

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.

More Pharmacology questions

Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is C, Isopropyl alcohol. Isopropyl alcohol is metabolised by alcohol dehydrogenase to acetone, which causes ketosis without significant acidosis, and the parent alcohol raises the osmolar gap.

Why is "Methanol" not the answer?

Methanol produces formic acid, severe anion gap acidosis and visual loss.

Why is "Ethylene glycol" not the answer?

Ethylene glycol produces oxalic acid, acidosis, hypocalcaemia and renal failure.

Why is "Propylene glycol" not the answer?

Propylene glycol causes lactic acidosis, and acetone ketosis is not a feature.

What concept does this question test?

It tests Toxicology and antidotes: isopropyl alcohol poisoning in Pharmacology. Methanol and ethylene glycol produce a high anion gap metabolic acidosis, with visual loss or crystalluria respectively.

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 and antidotes: isopropyl alcohol poisoning?

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.