Azithromycin is an antibiotic useful for the treatment of bacterial infections. It is an azalide, a subclass of macrolide antibiotic, and it has been discovered in 1980 by a team of researchers at the Croatian pharmaceutical company PLIVA – Gabrijela Kobrehel, Gorjana Radobolja-Lazarevski and Zrinka Tamburašev, led by Dr. Slobodan Đokić. Azithromycin was patented in 1981. In 1986, PLIVA and Pfizer signed a licensing agreement, which gave Pfizer exclusive rights for the sale of azithromycin in Western Europe and the United States. PLIVA launched its azithromycin on the market in Central and Eastern Europe under the brand name of Sumamed in 1988. Azitromycin is the most important pharmaceutical product ever produced in Croatia and with it Croatia became one of only few countries in the world with an original antibiotic.