Due to a low cost and general efficacy in common bacterial diseases , sulfonamides (SAs), the oldest antibacterial agents, are still widely used nowadays in human and veterinary medicine for the treatment and prophylactic purposes of infectious diseases and used as growth-promoting feed additives. General Properties of SAs Sulfonamides (SAs), derivatives of sulfanilamide, which is the nucleus common to all sulfonamides, are a large group of antimicrobial synthetic chemotherapeutic drugs. SAs are synthesized by adding or substituting different functional groups to the amido group or other amino groups, leading to compounds with a variety of physical, chemical, pharmacologic, and antibacterial properties. Currently, over 30 sulfonamides are used as antimetabolites in human and animal treatment, in a mechanism of blocking several enzymes that are needed for the biosynthesis of purine bases and necessary metabolic reactions for the formation of RNA. ...