Chemotherapy: primaquine and radical cure: 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 · Chemotherapy: primaquine and radical cure

Sample item

A 30-year-old man treated with chloroquine for Plasmodium vivax malaria, and now asymptomatic, needs prevention of relapse. Which is the best step?

AGive quinine for 7 daysBRepeat chloroquine for 14 days to clear liver formsCTest G6PD status, then give primaquine to eliminate hypnozoitesDGive artesunate monotherapy for 14 days

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

The answer and the reasoning

C. Test G6PD status, then give primaquine to eliminate hypnozoites

Plasmodium vivax forms dormant hypnozoites in the liver that cause relapse, and chloroquine does not kill them. Primaquine is the drug that eradicates them (radical cure), but it can cause severe haemolysis in G6PD deficiency, so the status is checked first and an adapted regimen is used in deficiency. It is avoided in pregnancy and in infants.

Option by option

A. Give quinine for 7 days
Quinine is a blood schizonticide and does not clear hypnozoites.
B. Repeat chloroquine for 14 days to clear liver forms
Chloroquine acts on blood schizonts and has no effect on hypnozoites.
C. Test G6PD status, then give primaquine to eliminate hypnozoites (correct)
Correct. Hypnozoite eradication needs an 8-aminoquinoline with a prior G6PD check.
D. Give artesunate monotherapy for 14 days
Artesunate treats the blood stages and does not clear hypnozoites.

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 C, Test G6PD status, then give primaquine to eliminate hypnozoites. Plasmodium vivax forms dormant hypnozoites in the liver that cause relapse, and chloroquine does not kill them.

Why is "Give quinine for 7 days" not the answer?

Quinine is a blood schizonticide and does not clear hypnozoites.

Why is "Repeat chloroquine for 14 days to clear liver forms" not the answer?

Chloroquine acts on blood schizonts and has no effect on hypnozoites.

Why is "Give artesunate monotherapy for 14 days" not the answer?

Artesunate treats the blood stages and does not clear hypnozoites.

What concept does this question test?

It tests Chemotherapy: primaquine and radical cure in Pharmacology. Primaquine is the drug that eradicates them (radical cure), but it can cause severe haemolysis in G6PD deficiency, so the status is checked first and an adapted regimen is used in deficiency. It is avoided in pregnancy and in infants.

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 Chemotherapy: primaquine and radical cure?

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.