Pyrimethamine (Daraprim) is a medication used for protozoal infections. It is commonly used as an antimalarial drug (for both treatment and prevention of malaria), and is also used (combined with sulfadiazine) in the treatment of Toxoplasma gondii infections in immunocompromised patients, such as HIV-positive individuals. Sulfadoxine (also spelled sulphadoxine) is an ultra-long-lasting sulfonamide often used in combination with pyrimethamine to treat or prevent malaria. It is also used, usually in combination with other drugs, to treat or prevent various infections in livestock. SULPHAMETHOPYRAZINE : This is a combination of N1-(5,6-dimethoxypyrimidin-4-yl)-sulphanilamide (sulphadoxine)and5-(4-chlorophenyl)-6-ethylpyrimidine-2,4-diyldiamin (pyrimethamine).