Sulfadoxine is a broad-spectrum sulfonamide antibiotic effective against gram-negative and gram-positive bacteria. It is commonly used against malaria, especially Plasmodium falciparum malaria with chloroquine resistance. It has been used to study Toxoplasma gondii infections and to prevent infections in post-surgical animal models.

Sulfamerazine is a sulfonamide antibiotic useful against a wide variety of gram-negative and gram-positive bacteria.It is involved in the characterization of chitosan membranes used for transporting drugs.

Sulfonamide antibiotics are derived from a chemical called sulfanilamide. They function through inhibiting the conversion of p-aminobenzoic acid to dihydropteroate, an essential step in the synthesis of folic acid. By preventing the production of folate in bacteria, the sulfonamide antibiotics ultimately suppress bacterial DNA replication.

Sulfamethazine is broad-spectrum sulfonamide antibiotic targeting bacteria causing bronchitis and urinary tract infections. It is used in disposition and depletion studies of kinetics and to develop procedures used for quantification. Sulfamethazine is also an inducer of CYP3A4.

Sulfamonomethoxine is a long-acting sulfonamide antibiotic. It is used in blood kinetic studies as well as to study the formation of capsules in Bordetella bronchiseptica. Sulfamonomethoxine is used to combat hyperpyrexia of unknown etiology.