Neuromuscular blockers: cisatracurium: 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 · Neuromuscular blockers: cisatracurium

Sample item

A patient with combined hepatic and renal failure needs a non-depolarising muscle relaxant for a prolonged procedure. Which drug is preferred because its elimination is largely independent of organ function?

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

The answer and the reasoning

C. Cisatracurium, eliminated by spontaneous Hofmann degradation

Atracurium and cisatracurium undergo spontaneous non-enzymatic Hofmann elimination at physiological pH and temperature (plus ester hydrolysis for atracurium), so their duration is not prolonged in hepatic or renal failure. Pancuronium and vecuronium depend on kidney and liver respectively, and block is prolonged in organ failure.

Option by option

  • A. Vecuronium, eliminated mainly by the liver

    Vecuronium is cleared mainly by hepatic uptake and biliary excretion.

  • B. Pancuronium, eliminated mainly by the kidney

    Pancuronium relies on renal excretion and also has a vagolytic effect.

  • C. Cisatracurium, eliminated by spontaneous Hofmann degradation (correct)

    Correct. Hofmann elimination occurs in plasma and does not need liver or kidney.

  • D. Rocuronium, eliminated mainly by hepatic uptake

    Rocuronium depends on hepatic clearance, so its action is prolonged in liver disease.

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 C, Cisatracurium, eliminated by spontaneous Hofmann degradation. Atracurium and cisatracurium undergo spontaneous non-enzymatic Hofmann elimination at physiological pH and temperature (plus ester hydrolysis for atracurium), so their duration is not prolonged in hepatic or renal failure.

Why is "Vecuronium, eliminated mainly by the liver" not the answer?

Vecuronium is cleared mainly by hepatic uptake and biliary excretion.

Why is "Pancuronium, eliminated mainly by the kidney" not the answer?

Pancuronium relies on renal excretion and also has a vagolytic effect.

Why is "Rocuronium, eliminated mainly by hepatic uptake" not the answer?

Rocuronium depends on hepatic clearance, so its action is prolonged in liver disease.

What concept does this question test?

It tests Neuromuscular blockers: cisatracurium in Pharmacology. Pancuronium and vecuronium depend on kidney and liver respectively, and block is prolonged in organ failure.

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 Neuromuscular blockers: cisatracurium?

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.