The Role of Drugs in a Malaria Program

SummaryWith new emphasis on malaria control as an alternative to malaria eradication, the use of drugs is assuming an increased importance. For various reasons, drugs available at present have a number of shortcomings. Drug resistance has appeared in some parts of the world.Of the major antimalarial drugs, some (e.g., chloroquine, pyrimethamine, and primaquine) have been in use for years. The sulfones and sulfonamides are of value in some conditions and particularly for treatment of falciparum malaria when chloroquine resistant strains are present.In malaria programs drugs are used for suppressive treatment and for radical cure. The 4-aminoquinolines may be combined with primaquine to relieve the primary clinical attack, to eliminate the gametocytes, and prevent relapses. Pyrimethamine is used mainly for its sporontocidal effect. When drugs are administered as “presumptive treatment” of an unconfirmed case of malaria, a schizontocide is given: during the surveillance activity of late attack and consolidation, gametocytocides may be called for. In mass drug administration, some combination of suppressive treatment, radical cure, and prevention of transmission is attempted.Chloroquine resistance first appeared only in South America and Southeast Asia; while its spread has been slow, the prevention and management of drug resistance are among the most important practical problems of malaria control. The sensitivity of plasmodia to all the known antimalarial drugs varies from strain to strain; actual resistance may occur with any drug, but seems to occur most rapidly with proguanil and pyrimethamine. At this time chloroquine is still indicated for suppression, except in the presence of known high levels of resistance.