Sulfonamide is a functional group (a part of a molecule) that is the basis of several groups of drugs, which are called sulphonamides, sulfa drugs or sulpha 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 upon the antibacterial sulfonamides. Allergies to sulfonamides are common. The overall incidence of adverse drug reactions to sulfa antibiotics is approximately 3%, close to penicillin; hence medications containing sulfonamides are prescribed carefully. Sulfonamide drugs were the first broadly effective antibacterials used systemically, and paved the way for the antibiotic revolution in medicine.
Function
In bacteria, antibacterial sulfonamides act as competitive inhibitors of the enzyme dihydropteroate synthase (DHPS), which is involved in folate synthesis. Sulfonamides are therefore bacteriostatic and inhibit bacterial growth and multiplication, but do not kill them. Humans, in contrast to bacteria, acquire folate (vitamin B9) through the diet.
Sulfonamides are used to treat allergies and coughs, and have antifungal and antimalarial functions. The moiety is also present in other medications that are not antimicrobials, including thiazide diuretics (including hydrochlorothiazide, metolazone, and indapamide, among others), loop diuretics (including furosemide, bumetanide, and torsemide), acetazolamide, sulfonylureas (including glipizide, glyburide, among others), and some COX-2 inhibitors (e.g., celecoxib). Sulfasalazine, in addition to its use as an antibiotic, is also used in the treatment of inflammatory bowel disease.
… excerpt ends here. Continue reading the full article.
