Does Zithromax treat upper respiratory infections?

Azithromycin, brand name Zithromax, is an antibiotic. Antibiotics are used to treat infections caused by bacteria. Azithromycin is usually not effective in treating upper respiratory infections caused by viruses such as the common cold or flu. It may sometimes be used to treat upper respiratory infections caused by bacteria like bronchitis or sinusitis but should only be taken if prescribed by a doctor.