Which of the following antimalarial is a slow acting schizonticide-
**Core Concept**
The question tests the student's knowledge of antimalarial drugs, specifically their mode of action against the malaria parasite. Slow-acting schizonticides target the erythrocytic stage of the parasite, where it multiplies within red blood cells. This class of antimalarials is crucial in the treatment of malaria, particularly in areas with high resistance to other drugs.
**Why the Correct Answer is Right**
The correct answer is a slow-acting schizonticide because it inhibits the growth and multiplication of the malaria parasite within red blood cells. This class of drugs works by targeting the schizont stage, which is the stage where the parasite undergoes asexual reproduction. The correct answer, **Chloroquine**, is a well-known slow-acting schizonticide that has been used for decades in the treatment of malaria. Chloroquine works by accumulating in the food vacuoles of the parasite, where it raises the pH and prevents the parasite from digesting its hemoglobin-based food source.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a fast-acting schizonticide, which works by rapidly killing the malaria parasite within red blood cells. Fast-acting schizonticides are often used in combination with other antimalarials to prevent resistance.
**Option B:** This option is incorrect because it is a blood schizonticide, but it is not slow-acting. Blood schizonticides target the erythrocytic stage of the parasite, but they work more quickly than slow-acting schizonticides.
**Option C:** This option is incorrect because it is not an antimalarial drug at all. It is a different type of medication altogether.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that slow-acting schizonticides like Chloroquine are often used in combination with other antimalarials to prevent resistance. This combination therapy is crucial in the treatment of malaria, particularly in areas with high resistance to other drugs.
**Correct Answer: C. Chloroquine**