Toxicology: salicylate: 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 · Toxicology: salicylate

Sample item

A 6-year-old child who swallowed aspirin tablets has tinnitus, fast deep breathing and fever. His arterial blood gas shows a mixed respiratory alkalosis and high anion gap metabolic acidosis. Which therapy increases elimination?

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

The answer and the reasoning

B. Intravenous sodium bicarbonate to alkalinise the urine

Salicylates stimulate the respiratory centre and uncouple oxidative phosphorylation, producing early respiratory alkalosis and later metabolic acidosis with hyperthermia. Alkalinising the urine to a pH of 7.5 to 8 ionises salicylic acid, trapping it in the tubular lumen and increasing excretion, while correcting serum acidosis also reduces tissue entry. Haemodialysis is needed in severe poisoning.

Option by option

  • A. Forced diuresis with large volumes of saline

    Forced diuresis risks fluid overload and does not enhance elimination.

  • B. Intravenous sodium bicarbonate to alkalinise the urine (correct)

    Alkalinisation traps ionised salicylate in urine and increases elimination.

  • C. Pralidoxime

    Pralidoxime reactivates cholinesterase and has no role here.

  • D. Ammonium chloride to acidify the urine

    Acidifying the urine would increase non-ionised salicylate reabsorption and worsen acidosis.

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 B, Intravenous sodium bicarbonate to alkalinise the urine. Salicylates stimulate the respiratory centre and uncouple oxidative phosphorylation, producing early respiratory alkalosis and later metabolic acidosis with hyperthermia.

Why is "Forced diuresis with large volumes of saline" not the answer?

Forced diuresis risks fluid overload and does not enhance elimination.

Why is "Pralidoxime" not the answer?

Pralidoxime reactivates cholinesterase and has no role here.

Why is "Ammonium chloride to acidify the urine" not the answer?

Acidifying the urine would increase non-ionised salicylate reabsorption and worsen acidosis.

What concept does this question test?

It tests Toxicology: salicylate in Pharmacology. Alkalinising the urine to a pH of 7.5 to 8 ionises salicylic acid, trapping it in the tubular lumen and increasing excretion, while correcting serum acidosis also reduces tissue entry. Haemodialysis is needed in severe poisoning.

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: salicylate?

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.