Strength: 500 mg. Dosage Form: Injection. Indications: Infections caused by susceptible strains. Description: Azithromycin for injection contains the active ingredient azithromycin, an azalide, a subclass of macrolide antibiotics, for intravenous injection. Ingredients: Azithromycin for injection, supplied in lyophilized form in a 10 mL single dose vial, contains an equivalent of 500 mg azithromycin for intravenous administration.