**Question:** Treatment of choice for chloroquine resistant malaria is -

A. Artemether
B. Quinine
C. Mefloquine
D. Primaquine

**Core Concept:**

Malaria is a parasitic infection caused by Plasmodium species, predominantly transmitted through the bite of infected Anopheles mosquitoes. Chloroquine is a widely used antimalarial drug, targeting the parasite's growth and maturation within the host red blood cells. However, chloroquine resistance has emerged as a significant challenge in malaria control programs, necessitating the use of alternative antimalarial drugs.

**Why the Correct Answer is Right:**

Drug resistance in malaria has led to a need for alternative therapies. Chloroquine resistance is mainly due to mutations in the Plasmodium parasite's dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS) enzymes, which are crucial for parasite survival. Primaquine is a 8-aminoquinoline drug, which targets the parasite's glycosomal glycerol kinase, leading to parasite death.

**Why Each Wrong Option is Incorrect:**

A. Artemether (synthetic dihydroartemisinin) and its lipid formulation (Coartem) are part of the artemisinin combination therapies (ACTs). Although effective against chloroquine-resistant malaria, they are not specific alternatives to chloroquine.

B. Quinine is an antimalarial drug derived from the bark of the Cinchona tree, mainly used for severe malaria and in combination with other drugs. It is not specifically recommended over chloroquine due to resistance.

C. Mefloquine is an antimalarial drug derived from quinine, mainly used for Plasmodium falciparum malaria. It is not specifically recommended over chloroquine due to resistance.

**Clinical Pearl:**

In endemic regions, it is essential for healthcare providers to accurately diagnose parasite resistance and prescribe the appropriate antimalarial therapy. Combination therapies like ACTs, including chloroquine, artemisinin derivatives, and quinine, should be used based on the parasite species and resistance patterns. Regular monitoring of drug efficacy and resistance patterns is crucial for effective malaria treatment.