Elizabeth Spencer, age 14, of Wilmington, Del., for her question:
WHEN WERE SULFA DRUGS DISCOVERED?
Sulfa drugs are a group of chemicals that are used to fight bacteria and some other organisms that cause disease in the body. Knowledge of their possible benefits dates back to 1908 when German chemist Paul Geimo discovered chemicals that eventually led to the sulfa drugs.
It was not until the early 1930s that sulfonamides, as sulfa drugs are also called, could be used in medicine. In 1935, German bacteriologist Gerhard Domagk reported that the sulfonamide drug Prontosil killed streptococcal bacteria in mice. (Domagk was chosen for the Nobel Prize in medicine in 1939 for his discovery, but the Nazi regime in Germany would not allow him to accept it.)
Research in this area spread quickly after Domagk's discovery. Researchers, particularly in France, England and the United States, investigated thousands of related chemicals before they found the few that were the most useful.
Prontosil and Neoprontosil are trade names for the two earliest sulfonamides. In the body, they release sulfanilamide, the substance that actively fights against bacteria.
Sulfanilamide, sulfapyrazine and sulfathiazole were among the earliest sulfa drugs put to general use. In time they were largely replaced by other, more effective, sulfonamides.
The sulfa drugs now used for general body infections include sulfadimethoxine, sulfamethazine, sulfisoxazole and sulfadiazine.
Thousands of lives have been saved with these valuable sulfa drugs. The use of sulfa drugs has reduced the death rate in one form of meningitis from about 50 out of every 100 cases to about five out of 100.
In general, sulfa drugs are used to treat diseases such as pneumonia, dysentery, meningitis, blood poisoning, urinary tract infections and some venereal diseases, as well as cellulitis, bubonic plague and cholera.
Normally, sulfa drugs do not actually kill bacteria. Instead, they prevent the bacteria from multiplying. Then the body's regular defenses usually kill the bacteria.
The sulfa drugs are most commonly taken by mouth or by injection into the blood. They may also be applied directly to the skin as an ointment or powder.
All sulfa drugs contain sulphur, nitrogen, hydrogen and oxygen. They are called sulfa drugs or sulfonamides because of their similar chemical makeup. But each one is a little different in structure.
Sulfonamides are not effective against all bacteria. For example, they are not effective against organisms causing tuberculosis. Doctors often must identify the type of bacteria that is causing an infection before they know whether to use a sulfa drug.