Acetylator phenotype and response of individuals infected with a chloroquine-resistant strain of Plasmodium falciparum to sulfalene and pyrimethamine.

Acetylator phenotype was determined in 33 volunteers who were infected with a chloroquine-resistant strain of Plasmodium falciparum and who received, for cure, 2 g of sulfalene and 50 mg of pyrimethamine. This drug combination did not cure 5 of 14 rapid acetylators and 3 of 19 slow acetylators. This difference is not significant. Plasma levels of non-acetylated sulfalene, acetylated sulfalene, acetylation, and biologic half-life of non-acetylated sulfalene after administration of the combination did not differ importantly between the two groups. Acetylator phenotype does not appear to influence the response to sulfalene and pyrimethamine of individuals infected with chloroquine-resistant falciparum malaria.