Combinations of 4-aminobenzoic acid competitors and dihydrofolate dehydrogenase inhibitors in the chemotherapy of malaria. A commentary.

Potentiating combinations of 4-aminobenzoic acid (PABA) competitors, such as sulfadoxine, sulfalene, or dapsone, and dihydrofolate dehydrogenase(a) (1.5.1.4) inhibitors, such as pyrimethamine or proguanil, have been subjected to various trials over the last decade. By and large they have proved to be effective agents against drug-resistant strains of malaria parasites, and with the small doses required they have been free of toxic effects. Parasite resistance to such combinations has seldom occurred but may be associated with cross-resistance to other combinations. These combinations should be reserved for the treatment of chloroquine-resistant infections and for use as adjuvants in organized malaria eradication campaigns.