What is "sulfonamide"

alt. 1 (context chemistry English) Any amide of a sulfonic acid RS(=O)₂NR'₂. 2 (context pharmaceutical drug English) Any of a group of antibiotics; a sulfa drug. n. 1 (context chemistry English) Any amide of a sulfonic acid RS(=O)₂NR'₂. 2 (context pharmaceutical drug English) Any of a group of antibiotics; a sulfa drug.

n. antibacterial consisting of any of several synthetic organic compounds capable of inhibiting the growth of bacteria that require PABA [syn: sulfa drug, sulfa, sulpha]

Sulfonamide (also called sulphonamide, sulfa drugs or sulpha drugs) is the basis of several groups of drugs. The original antibacterial sulfonamides are synthetic antimicrobial agents that contain the sulfonamide group. Some sulfonamides are also devoid of antibacterial activity, e.g., the anticonvulsant sultiame. The sulfonylureas and thiazide diuretics are newer drug groups based on the antibacterial sulfonamides.

Allergies to sulfonamide are common. According to data the overall incidence of adverse drug reactions to sulfa antibiotics is approximately 3%, close to penicillin; hence medications containing sulfonamides are prescribed carefully. It is important to make a distinction between sulfa drugs and other sulfur-containing drugs and additives, such as sulfates and sulfites, which are chemically unrelated to the sulfonamide group, and do not cause the same hypersensitivity reactions seen in the sulfonamides.

Because sulfonamides displace bilirubin from albumin, kernicterus (brain damage due to excess bilirubin) is an important potential side effect of sulfonamide use.

Sulfonamide or sulphonamide may refer to:

• Sulfonamide (chemistry) – the sulfonamide functional group in organic chemistry
• Sulfonamide (medicine) – the group of sulfonamide antibacterial drugs.

In chemistry, the sulfonamide functional group (also spelt sulphonamide) is -S(=O)-NH, a sulfonyl group connected to an amine group. Relatively speaking this group is unreactive. The amine center is no longer basic. The S-N bond is cleaved only with difficulty. Because of the rigidity of the functional group, sulfonamides are typically crystalline. For this reason, the formation of a sulfonamide is a classic method to convert an amine into a crystalline derivative which can be identified by its melting point. Many important drugs contain the sulfonamide group.

A sulfonamide (compound) is a compound that contains this group. The general formula is RSONH, where R is some organic group. For example, "methanesulfonamide" is CHSONH. Any sulfonamide can be considered as derived from a sulfonic acid by replacing a hydroxyl group with an amine group. In medicine, the term "sulfonamide" is sometimes used as a synonym for sulfa drug, a derivative or variation of sulfanilamide. The first sulfonamide was discovered in Germany in 1932.