Azithromycin 500mg is a macrolide antibiotic used to treat bacterial infections of the respiratory tract (acute bronchitis, community‑acquired pneumonia), sinuses, throat, and ears, as well as skin and soft‑tissue infections. It is an alternative for streptococcal pharyngitis in those who cannot take first‑line β‑lactams. Azithromycin also treats certain sexually transmitted infections, including uncomplicated urethritis and cervicitis due to Chlamydia trachomatis and some cases involving Neisseria gonorrhoeae, and is used for chancroid in men. In people with advanced HIV, it helps prevent or treat disseminated Mycobacterium avium complex (MAC). It is ineffective against viral illnesses and should be used when bacterial infection is suspected.