Tetracycline, << TEHT ruh `sy` klihn, >> is any of a family of antibiotics used to treat infections. The tetracyclines affect many kinds of bacteria and other microorganisms, including rickettsias (see Rickettsia ). Doctors use tetracyclines to treat such serious diseases as typhus and Rocky Mountain spotted fever. They also use tetracyclines in the treatment of acne.
The first tetracycline became available in 1948. Since then, tetracyclines have been widely—and often inappropriately—used to treat a great variety of diseases. This widespread use caused many microorganisms to become resistant to the effects of these antibiotics. As a result, tetracyclines are no longer effective against diseases caused by these microorganisms.
All the tetracyclines fight most of the same microorganisms. They differ chiefly in how well they are absorbed by the body and in how long their effects last. Tetracyclines act by blocking the process by which bacteria make proteins. Although generally safe, tetracyclines can cause many side effects. For example, large doses of these antibiotics can seriously damage the liver and kidneys. In addition, tetracyclines can permanently discolor developing teeth. For this reason, doctors do not prescribe tetracyclines in treating children and pregnant women.
