Sulfanilamide is the parent compound of a group of pharmaceuticals known as sulfa drugs. Sometimes referred to as sulfonamides, sulfa drugs were the first chemical substances utilized to cure and prevent serious bacterial infections in humans and, therefore, represent a significant step forward along the path to modern medicine.

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Though synthesized in 1908 by Austrian chemist Paul Gelmo, many years would pass before the antibacterial action of sulfanilamide was realized. Indeed, it was not until 1932 that the German scientist Gerhard Domagk discovered that a red dye called Prontosil showed activity against streptococcal infections, and nearly three more years went by before French researchers found that its active antibacterial agent was sulfanilamide. However, soon after this realization, new sulfa drugs, most of which were more potent and less toxic than the compound from which they were derived, were produced and introduced to the pharmaceuticals market at a considerable pace.

Sulfanilamide and it derivative sulfa drugs are bacteriostatic, gaining their effectiveness by interfering with the enzymatic systems of bacteria and inhibiting their ability to grow or multiply. Due to the capacity of some bacteria to adapt in such a way that makes them resistant to this bacteriostatic action, a tremendous number of the sulfa drugs that originally appeared to be effective, no longer exhibit antibacterial action. Moreover, the toxicity of many sulfonamides, which some individuals are hypersensitive to, has also limited their use in recent years as the array of safer antibiotics available has expanded. Nevertheless, some sulfa drugs are still commonly utilized in the treatment of certain medical conditions, especially vulvovaginitis and urinary tract infections.

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