CHLOROGUANIDE

also called proguanil synthetic drug introduced into medicine in the 1940s to suppress and prevent malaria. Chloroguanide is administered orally for effective control of the malarial parasites Plasmodium falciparum and, to a lesser extent, P. vivax and P. malariae. It suppresses the activity of P. falciparum and usually eradicates the infection. The drug must be administered daily because it is eliminated quickly. It rarely produces side effects. By the late 20th century, P. falciparum had acquired resistance to chloroguanide in many areas of the world, thus reducing the drug's usefulness.