antimalarial

An antimalarial is a drug that targets Plasmodium, the single-celled parasite that causes malaria after a mosquito's bite. Malaria has shaped human history, and antimalarials are among the oldest and most globally important medicines — quinine from cinchona bark was used for centuries before its successors arrived.

These drugs strike the parasite at vulnerable points in its complex life cycle inside red blood cells. Many — including chloroquine — interfere with how the parasite safely disposes of toxic heme released as it digests hemoglobin, so the parasite poisons itself. Artemisinin, a peroxide-bridged natural product from sweet wormwood, is activated by iron inside the parasite to unleash damaging radicals, and is today's frontline agent.

Antimalarials are used both to treat active disease and to prevent it in travellers, and some also hit the liver or transmission stages. The honest and urgent caveat is resistance: chloroquine resistance is now widespread, and emerging artemisinin resistance is why current treatment uses artemisinin-based combination therapy — pairing the fast-acting drug with a partner to protect both.