Antimalarials: radical cure of vivax: 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 · Antimalarials: radical cure of vivax

Sample item

A 25-year-old man has completed chloroquine for P. vivax malaria and the blood smear is now negative. To prevent relapses, which drug should be given, and what must be checked first?

APrimaquine, after checking G6PD statusBDoxycycline, after checking pregnancy statusCChloroquine again, after repeating the smearDArtesunate, after checking renal function

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

The answer and the reasoning

A. Primaquine, after checking G6PD status

Chloroquine kills blood schizonts but not the dormant hepatic hypnozoites of P. vivax that cause relapse. Primaquine is the tissue schizonticide for radical cure, but it causes haemolysis in G6PD deficiency, so G6PD status is checked beforehand. Primaquine is avoided in pregnancy and infancy.

Option by option

A. Primaquine, after checking G6PD status (correct)
Correct. Primaquine eradicates hypnozoites, and G6PD deficiency risks haemolysis.
B. Doxycycline, after checking pregnancy status
Doxycycline is a slow blood schizonticide used for prophylaxis and does not kill hypnozoites.
C. Chloroquine again, after repeating the smear
Repeating chloroquine does not act on liver hypnozoites.
D. Artesunate, after checking renal function
Artesunate is a blood schizonticide and does not eliminate 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 A, Primaquine, after checking G6PD status. Chloroquine kills blood schizonts but not the dormant hepatic hypnozoites of P.

Why is "Doxycycline, after checking pregnancy status" not the answer?

Doxycycline is a slow blood schizonticide used for prophylaxis and does not kill hypnozoites.

Why is "Chloroquine again, after repeating the smear" not the answer?

Repeating chloroquine does not act on liver hypnozoites.

Why is "Artesunate, after checking renal function" not the answer?

Artesunate is a blood schizonticide and does not eliminate hypnozoites.

What concept does this question test?

It tests Antimalarials: radical cure of vivax in Pharmacology. vivax that cause relapse. Primaquine is the tissue schizonticide for radical cure, but it causes haemolysis in G6PD deficiency, so G6PD status is checked beforehand. Primaquine is avoided in pregnancy and infancy.

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 Antimalarials: radical cure of vivax?

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.