Ciprofloxacin

Ciprofloxacin, often called Cipro, its original trade name, is one of the world’s most widely prescribed antibiotics for bacterial infections. It is a member of the quinoline antibacterial class and is a descendant of norfloxacin, the first quinoline antibiotic to contain a fluorine atom.

In the 1980s, scientists at Bayer Pharmaceuticals discovered that replacing the ethyl group of norfloxacin with a cyclopropyl group greatly increased its Gram-negative bactericidal activity. In 1987, Bayer received US Food and Drug Administration approval for orally administered ciprofloxacin; the intravenous form was approved in 1991.

Since Bayer’s patent expired in 2004, ciprofloxacin has been widely distributed as an inexpensive broad-spectrum antibacterial. It is on the World Health Organization's List of Essential Medicines.