Treatment of Falciparum Malaria Caused by Strain Resistant to Quinine

Malaria caused by the Vietnam (Smith) strain ofPlasmodium falciparum,isolated from a patient in the United States in 1969, is insusceptible to treatment with chloroquine phosphate, pyrimethamine, and chloroguanide hydrochloride. Radical cure has been obtained in some infected nonimmune patients by the use of quinine in courses of 8.1 gm (base) or more, but in other patients the infection has recrudesced following 22.7 gm (base) given over 14 days; in one patient despite demonstrated normal absorption the latter treatment failed to produce improvement, while addition of pyrimethamine in another did not clear parasitemia. Radical cure was achieved in an average time of 3 days in all of seven men receiving 18.9 gm (base) of quinine over 14 days (1.66 gm of quinine sulfate each day), with 1.0 gm of sulfalene given in four divided doses on the first day.