Sulfonamides, also known as sulfa drugs, are a group of synthetic antibiotics that were among the first to be used in medicine. They work by inhibiting the growth of bacteria, specifically by interfering with the synthesis of folic acid, which is essential for bacterial reproduction. Sulfonamides are effective against a variety of bacterial infections and have been used to treat conditions such as urinary tract infections and certain types of pneumonia. Although their use has declined with the advent of more advanced antibiotics, sulfonamides remain important in certain medical situations. They are often used in combination with other medications to enhance their effectiveness. Some common examples of sulfonamides include sulfamethoxazole and sulfadiazine, which are still prescribed today for specific infections.