Obstetric anaesthesia: magnesium in pre-eclampsia: practice question

A Anaesthesia 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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Anaesthesia · Obstetric anaesthesia: magnesium in pre-eclampsia

Sample item

A woman with severe pre-eclampsia on magnesium sulphate needs caesarean section. How does magnesium influence anaesthetic management?

AIt prevents hypotension after spinalBIt antagonises non-depolarising blockersCIt potentiates neuromuscular blockers, so doses are reduced and monitoredDIt makes suxamethonium ineffective

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

The answer and the reasoning

C. It potentiates neuromuscular blockers, so doses are reduced and monitored

Magnesium reduces acetylcholine release and potentiates both depolarising and non-depolarising relaxants. Loss of patellar reflexes occurs at about 8 to 10 mEq/L, and calcium gluconate 1 g reverses toxicity.

Option by option

A. It prevents hypotension after spinal
Magnesium does not prevent spinal hypotension.
B. It antagonises non-depolarising blockers
Magnesium potentiates rather than antagonises.
C. It potentiates neuromuscular blockers, so doses are reduced and monitored (correct)
Correct. Reduced relaxant doses and monitoring are needed.
D. It makes suxamethonium ineffective
Suxamethonium remains effective.

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.

Questions about this Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is C, It potentiates neuromuscular blockers, so doses are reduced and monitored. Magnesium reduces acetylcholine release and potentiates both depolarising and non-depolarising relaxants.

Why is "It prevents hypotension after spinal" not the answer?

Magnesium does not prevent spinal hypotension.

Why is "It antagonises non-depolarising blockers" not the answer?

Magnesium potentiates rather than antagonises.

Why is "It makes suxamethonium ineffective" not the answer?

Suxamethonium remains effective.

What concept does this question test?

It tests Obstetric anaesthesia: magnesium in pre-eclampsia in Anaesthesia. Loss of patellar reflexes occurs at about 8 to 10 mEq/L, and calcium gluconate 1 g reverses toxicity.

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 Obstetric anaesthesia: magnesium in pre-eclampsia?

Make a table of each agent, its key advantage and its main side effect. Then use the flashcards and the other Anaesthesia 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.