Chloroquine

Lore & Background

It is a member of the drug class 4-aminoquinoline. As an antimalarial, it works against the asexual form of the malaria parasite within red blood cells by increasing heme levels, which are toxic to the parasite. It has been used in mass drug administrations, which may have contributed to resistance, particularly in Plasmodium falciparum. The Centers for Disease Control and Prevention recommend against treatment of malaria with chloroquine alone due to more effective combinations.

Reader's Guide

Chloroquine's significance lies in its long history as a frontline antimalarial and its repurposing for autoimmune diseases. However, widespread resistance, especially in Plasmodium falciparum, has limited its use in malaria, requiring alternative medications like mefloquine or atovaquone in resistant areas. Its safety in pregnancy appears favorable, though formal studies are lacking. The drug's toxicity in overdose (about 20% risk of death) and potential for irreversible retinal damage with long-term use necessitate careful monitoring. Its inclusion on the WHO Essential Medicines List underscores its continued value, particularly in resource-limited settings, despite emerging resistance and side-effect concerns.

Did You Know?

• It is on the World Health Organization's List of Essential Medicines.
• Chloroquine-induced itching is very common among black Africans (70%) but much less common in other races.
• In overdose, chloroquine has a risk of death of about 20%.