Zmax (generic: azithromycin) is a prescription medication used to treat many bacterial infections such as bronchitis, pneumonia, sexually transmitted diseases, and infections of the ear, sinuses, skin, and throat. Zmax belongs to a group of drugs called macrolide antibiotics. It works by preventing the growth of bacteria.

This medication comes in an extended-release liquid form, and in single-dose packets to be mixed with water. Zmax is taken as one dose, on an empty stomach.

Common side effects of Zmax include diarrhea, nausea, stomach pain, and headache.