Abstract
The combination of a long-acting sulfonamide, sulfalene, and a dihydrofolic acid reductase inhibitor, trimethoprim, proved to be effective as a radical cure against a normal, as well as a chloroquine-quinine-pyrimethamine-resistant Plasmodium falciparum in nonimmune volunteers. The malaria caused by normal P. falciparum was cured (8 of 8 cases) by sulfalene (0.25 g) plus trimethoprim (0.125 g) administered as a single dose. Sulfalene (0.75 g) plus trimethoprim (0.5 g) combined cured 10 of 11 patients with malaria caused by chloroquine-pyrimethamine-quinine-resistant P. falciparum. Attempts to induce resistance to the combination have been unsuccessful thus far. The speed of action in clearance of parasites and lysis of fever compares favorably with that of chloroquine at its best. The combination is easily tolerated as a single dose.