SULPHADOXINE IS AN ANTIMALARIAL AGENT, WHICH ACTS BY RECIPROCAL POTENTIATION OF ITS TWO COMPONENTS, ACHIEVE BY A SEQUENTIAL BLOCKADE OF TWO ENZYMES INVOLVED IN THE BIOSYNTHESIS OF FOLINIC ACID WITHIN THE PARASITES. SULPHADOXINE IS EFFECTIVE AGAINST CERTAIN STRAINS OF PLASMODIUM FALCIPARUM THAT ARE RESISTANT TO CHLOROQUINE.