Drugs in pregnancy: magnesium sulfate regimens: 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 · Drugs in pregnancy: magnesium sulfate regimens

Sample item

A woman with severe pre-eclampsia has an eclamptic fit, and magnesium sulfate is started using the Pritchard regimen. Which description is correct?

AA single 10 g intramuscular doseBA 4 g intravenous loading dose plus 10 g intramuscular, then 5 g intramuscular every 4 hours alternately in each buttockCOral magnesium 1 g thrice dailyDA 4 g intravenous dose, then 1 g per hour infusion as the only element of Pritchard

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

The answer and the reasoning

B. A 4 g intravenous loading dose plus 10 g intramuscular, then 5 g intramuscular every 4 hours alternately in each buttock

The Pritchard regimen gives 4 g intravenously with 10 g intramuscularly (5 g in each buttock) followed by 5 g intramuscularly every four hours, while the Zuspan regimen uses 4 g intravenous loading followed by 1 g per hour infusion. Patellar reflexes, respiratory rate and urine output are monitored, and calcium gluconate reverses toxicity.

Option by option

A. A single 10 g intramuscular dose
A single dose is inadequate.
B. A 4 g intravenous loading dose plus 10 g intramuscular, then 5 g intramuscular every 4 hours alternately in each buttock (correct)
Correct. This describes the Pritchard regimen.
C. Oral magnesium 1 g thrice daily
Oral magnesium is not used for eclampsia.
D. A 4 g intravenous dose, then 1 g per hour infusion as the only element of Pritchard
That describes the Zuspan regimen.

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 Pharmacology question

What is the answer to this Pharmacology question?

The best answer is B, A 4 g intravenous loading dose plus 10 g intramuscular, then 5 g intramuscular every 4 hours alternately in each buttock. The Pritchard regimen gives 4 g intravenously with 10 g intramuscularly (5 g in each buttock) followed by 5 g intramuscularly every four hours, while the Zuspan regimen uses 4 g intravenous loading followed by 1 g per hour infusion.

Why is "A single 10 g intramuscular dose" not the answer?

A single dose is inadequate.

Why is "Oral magnesium 1 g thrice daily" not the answer?

Oral magnesium is not used for eclampsia.

Why is "A 4 g intravenous dose, then 1 g per hour infusion as the only elemen…" not the answer?

That describes the Zuspan regimen.

What concept does this question test?

It tests Drugs in pregnancy: magnesium sulfate regimens in Pharmacology. Patellar reflexes, respiratory rate and urine output are monitored, and calcium gluconate 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 Drugs in pregnancy: magnesium sulfate regimens?

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.