Antimalarial medications or simply antimalarials are a type of antiparasitic chemical agent, often naturally derived, that can be used to treat or to prevent malaria, in the latter case, most often aiming at two susceptible target groups, young children and pregnant women.
Antimalarial drugs are used for the treatment and prevention of malaria infection. Most antimalarial drugs target the erythrocytic stage of malaria infection, which is the phase of infection that causes symptomatic illness. The extent of pre-erythrocytic (hepatic stage) activity for most antimalarial drugs is not well characterized.
Treatment of the acute blood stage infection is necessary for malaria caused by all malaria species. In addition, for infection due to Plasmodium ovale or Plasmodium vivax, terminal prophylaxis is required with a drug active against hypnozoites (which can remain dormant in the liver for months and, occasionally, years after the initial infection).