(sulpha drug) n. one of a group of drugs, derived from sulphanilamide (a red dye), that prevent the growth of bacteria (i.e. they are bacteriostatic). Sulphonamides are effective against a variety of infections and were formerly widely used; because many of them are rapidly excreted and very soluble in the urine, they were particularly useful in treating infections of the urinary tract.
A variety of side-effects may occur with sulphonamide treatment, including nausea, vomiting, headache, and loss of appetite; more severe effects include *cyanosis, blood disorders, skin rashes, and fever. Because of increasing bacterial resistance to sulphonamides, and with the development of more effective less toxic antibiotics, the clinical use of these drugs has declined. Those still used include *sulfadiazine, *sulfasalazine, and sulfamethoxazole (combined with trimethoprim in *co-trimoxazole).
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