Fred McKenney, age 13, of Vancouver, Wash., for his question:
WHEN WERE SULFA DRUGS DISCOVERED?
Sulfa drugs are a group of chemicals that are used to fight bacteria and other organisms that cause disease in the body. The drugs are also called sulfonamides. Knowledge of the possible benefits from them dates back 81 years to 1908.
In 1908, a German chemist named Paul Gelmo was looking for better dyes for woolen goods. He discovered some chemicals that eventually led to the sulfa drugs. But it was not until the early 1930s that sulfonamides could be used in medicine.
In 1935, a German bacteriologist named Gerhard Domagk reported that the sulfonamide drug Prontosil killed streptococcal bacteria in mice. He was offered the Nobel prize in medicine for 1939 for his discovery, but the Nazi regime would not allow him to accept it.
Research in the new chemical 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 named for two of the earliest sulfonamides. In the body, they release sulfanilamide, the active substance that fights against bacteria.
Sulfanilamide, sulfapyrazine and sulfathiazole were among the earliest sulfa drugs put into general use. But in time they were largely replaced by other sulfonamides that were more effective and had less harmful side effects.
In general, sulfa drugs have been and still are used to treat diseases such as pneumonia, dysentery, meningitis, blood poisoning, urinary tract infections and some venereal diseases.
Sulfonamides are not effective against all bacteria. They are not, for example, effective against organisms causing tuberculosis. Therefore, doctors often must identify the type of bacteria that are causing an infection before they know whether to use a sulfa drug.
For the drug to be effective, there must be a concentration of sulfa in the body.
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.
Many bacteria need a chemical called para amino benzoic acid (PABA) to multiply. PABA acts like a necessary vitamin for these bacteria.
The sulfonamide drugs have a chemical structure similar to PABA, but they have sulfur atoms where PABA has carbon atoms. Bacteria cannot tell the difference between the two and absorb the sulfa drug rather than the PABA. The sulfur atoms then stop one or more of the growth processes of the bacteria and the bacteria cannot multiply.
All sulfa drugs contain sulfur, 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.