Azithromycin

Zithromax

Approved uses

• Acute bacterial exacerbations of chronic bronchitis in adults
• Acute bacterial sinusitis in adults
• Uncomplicated skin and skin structure infections in adults
• Urethritis and cervicitis in adults
• Genital ulcer disease in men
• Acute otitis media in pediatric patients (6 months of age and older)

Forms and strengths

• ZITHROMAX tablets 250 mg and 500 mg
• ZITHROMAX for oral suspension 100 mg/5 mL and 200 mg/5 mL

How it is taken

• Recommended Dosage for Adult Patients
• Infection Recommended Dose/Duration of Therapy Community-acquired pneumonia (mild severity)
• Pharyngitis/tonsillitis (second-line therapy)
• Skin/skin structure (uncomplicated) 500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2 through 5. Acute bacterial exacerbations of chronic bronchitis (mild to moderate) 500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2 through 5 or 500 mg once daily for 3 days. Acute bacterial sinusitis 500 mg once daily for 3 days. Genital ulcer disease (chancroid)
• Non-gonococcal urethritis and cervicitis One single 1 gram dose. Gonococcal urethritis and cervicitis One single 2 gram dose. Recommended Dosage for Pediatric Patients
• Infection Recommended Dose/Duration of Therapy Acute otitis media (6 months of age and older) 30 mg/kg as a single dose or 10 mg/kg once daily for 3 days or 10 mg/kg as a single dose on Day 1 followed by 5 mg/kg/day on Days 2 through 5. Acute bacterial sinusitis (6 months of age and older) 10 mg/kg once daily for 3 days.

Must not be used when

• Patients with known hypersensitivity to azithromycin, erythromycin, any macrolide or ketolide drug.
• Patients with a history of cholestatic jaundice/hepatic dysfunction associated with prior use of azithromycin. Hypersensitivity ZITHROMAX is contraindicated in patients with known hypersensitivity to azithromycin, erythromycin, any macrolide or ketolide drug.

Interactions

• Nelfinavir: Close monitoring for known adverse reactions of azithromycin, such as liver enzyme abnormalities and hearing impairment, is warranted.
• Warfarin: Use with azithromycin may increase coagulation times; monitor prothrombin time. Nelfinavir Co-administration of nelfinavir at steady-state with a single oral dose of azithromycin resulted in increased azithromycin serum concentrations.

Warnings and precautions

• Serious (including fatal) allergic and skin reactions: Discontinue ZITHROMAX if reaction occurs.
• Hepatotoxicity: Severe, and sometimes fatal, hepatotoxicity has been reported. Discontinue ZITHROMAX immediately if signs and symptoms of hepatitis occur.
• Infantile Hypertrophic Pyloric Stenosis (IHPS): Following the use of azithromycin in neonates (treatment up to 42 days of life), IHPS has been reported. Direct parents and caregivers to contact their physician if vomiting or irritability with feeding occurs.
• Prolongation of QT interval and cases of torsades de pointes have been reported. This risk which can be fatal should be considered in patients with certain cardiovascular disorders including known QT prolongation or history torsades de pointes, those with proarrhythmic conditions, and with other drugs that prolong the QT interval.
• Cardiovascular Death: Some observational studies have shown an approximately two-fold increased short-term potential risk of acute cardiovascular death in adults exposed to azithromycin relative to other antibacterial drugs, including amoxicillin. Consider balancing this potential risk with treatment benefits when prescribing ZITHROMAX.
• Clostridioides difficile -Associated Diarrhea: Evaluate patients if diarrhea occurs.
• ZITHROMAX may exacerbate muscle weakness in persons with myasthenia gravis. Hypersensitivity Serious allergic reactions, including angioedema, anaphylaxis, and dermatologic reactions including Acute Generalized Exanthematous Pustulosis (AGEP), Stevens-Johnson syndrome, and toxic epidermal necrolysis have been reported in patients on azithromycin therapy. Fatalities have been reported.

Common side effects

• Most common adverse reactions are diarrhea (5 to 14%), nausea (3 to 18%), abdominal pain (3 to 7%), or vomiting (2 to 7%).
• most common adverse reactions in patients receiving a single-dose regimen of 1 gram of ZITHROMAX were related to the gastrointestinal system and were more frequently reported than in patients receiving the multiple-dose regimen.

Pregnancy

Available data from published literature and postmarketing experience over several decades with azithromycin use in pregnant women have not identified any drug-associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes (see Data).

How it acts

Azithromycin is a macrolide antibacterial drug. Mechanism of Action Azithromycin acts by binding to the 23S rRNA of the 50S ribosomal subunit of susceptible microorganisms inhibiting bacterial protein synthesis and impeding the assembly of the 50S ribosomal subunit. Resistance Azithromycin demonstrates cross resistance with erythromycin.

Label holder:

Pfizer Laboratories Div Pfizer Inc

Label version:

24 July 2026

This section reports the approved product information. The wording is condensed from the regulator's own summary, and the full document is linked under Sources.