Which one of the following drug may be used for prevention of relapse of P. vivax infection –
**Core Concept**
The question is testing the knowledge of antimalarial drugs, specifically those used for the prevention of relapse of Plasmodium vivax infection. P. vivax has a dormant liver stage, known as hypnozoites, which can cause relapses if not treated.
**Why the Correct Answer is Right**
The correct answer is a drug that targets the liver stage of the parasite. Primaquine is a 8-aminoquinoline that is effective against the hypnozoites of P. vivax. It works by generating reactive oxygen species that damage the parasite's DNA, ultimately leading to the death of the hypnozoites. This prevents the recurrence of P. vivax infection.
**Why Each Wrong Option is Incorrect**
**Option A:** Chloroquine is an antimalarial drug that targets the blood stage of the parasite, but it is not effective against the liver stage of P. vivax.
**Option B:** Artemisinin is a fast-acting antimalarial drug that targets the blood stage of the parasite, but it is not effective against the liver stage of P. vivax.
**Option C:** Mefloquine is an antimalarial drug that targets the blood stage of the parasite, but it is not effective against the liver stage of P. vivax.
**Clinical Pearl / High-Yield Fact**
It is essential to note that primaquine should be used with caution in patients with G6PD deficiency, as it can cause hemolysis.
**Correct Answer:** C. Primaquine.