Azithromycin: a new 15-membered macrolide.

Azithromycin is the sole member of the macrolide sub-class, the azalides. Due to its altered chemical structure, azithromycin is characterized by a broader spectrum of activity, lower incidence of adverse events and drug interactions and a pharmacokinetic profile, that is in contrast to existing macrolides. Because of its high and prolonged cellular and tissue concentrations, patients are able to complete a course of azithromycin within a shorter timeframe as compared to other antibiotics. Azithromycin is widely used in the treatment of adult and pediatric respiratory tract infections. Continued research into azithromycin's utility has resulted in indication development for several devastating infections such as trachoma. Large-scale studies of its activity against Chlamydia pneumoniae related atherosclerosis are underway.