Title: sulfa drug | Infoplease
Headings: sulfa drug
sulfa drug
Content: The parent compound, para-aminobenzenesulfonamide, was synthesized in 1908 by Paul Gelmo, an Austrian industrial chemist. In 1932 the German chemist Gerhard Domagk discovered that the dye Prontosil had antagonistic properties against a wide range of bacteria, and in 1935 it was found that the sulfanilamide portion of the Prontosil molecule was responsible for its antibacterial effect. In 1940 it was shown that sulfanilamide inhibited the action of the physiological substance para-aminobenzoic acid, which bacteria need to synthesize folic acid. The idea that the two substances were antagonists led to a theory of the mechanism of action of drugs: Many chemotherapeutic substances compete with structurally similar substances that are necessary to the metabolism of invading microorganisms. Since sulfanilamide first came into use, more than 150 different derivatives have appeared on the market, chemically modified to achieve more effective antibacterial activity, wider spectrum of microorganisms affected, or more prolonged action. Because of their low cost they are still used in many parts of the world. However, resistance to sulfa drugs has emerged among many microorganisms, especially streptococci, meningococci, and shigella, making them less effective than formerly (see drug resistance ). The substances are still used to treat some urinary tract infections, leprosy, and in combination with other drugs, some fungal diseases and toxoplasmosis. The Columbia Electronic Encyclopedia, 6th ed.