SULFONAMIDES

They have some inhibitory influence on the erythrocytic phase, specially of P.falciparum. However they form supra-additive synergistic combination with pyrimethamine due to sequential block. Such combinations are now preferred for the prophylaxis as well as treatment of malaria. Though both components are slow acting, the combination is faster, so that it can be employed as a clinical curative as well. Development of resistance is also retarded.