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a medicinal preparation for the treatment and prophylaxis of malaria. Antimalarials are classified into several groups according to their selective or predominant effect on various forms of plasmodia. For example, quinacrine hydrochloride, chloroquine, and quinine kill schizonts in the blood and rapidly curtail malarial attacks, while quinocide and primaquine destroy malarial parasites in tissues and prevent future relapses of tertian and quartan malaria. For this reason, drugs of both groups are usually used with the above forms of malaria. Proguanil hydrochloride acts on the erythrocytic and sexual forms of plasmodia; it is especially effective against the pathogen that produces falciparum malaria. Quinocide and primaquine also kill the gamonts of pathogens and, as a result, the infected person remains noninfective for the mosquito. Quinine is usually used in regions where the pathogens that produce falciparum malaria are resistant to chloroquine. The administration of antimalarials, such as chloroquine, to healthy individuals is used in the chemoprophylaxis of malarial foci.
Most antimalarials are obtained synthetically. Quinine, for example, is an alkaloid of a cinchona tree. Antimalarials are also used to treat certain diseases caused by protozoans or helminths; for example, quinacrine hydrochloride is used to treat amebiasis, giardiasis, and leishmaniasis, while pyrimethamine is used to treat toxoplasmosis.
REFERENCEMoshkovskii, Sh. D., ed. Ukazaniia po lecheniiu i khimioprofilaktike maliarii. Moscow, 1972.
N. N. PLOTNIKOV