Last reviewed 2026-04-20 · How we verify

Zithromax (Azithromycin)

Azithromycin is a macrolide antibacterial drug.

Azithromycin is a macrolide antibacterial indicated for mild to moderate infections caused by susceptible bacteria in adults and pediatric patients. The drug demonstrates variable protein binding (51-7%), a long half-life (69-72 hours), and extensive tissue distribution with limited CNS penetration. Key contraindications include hypersensitivity to macrolides and prior cholestatic jaundice, with significant interactions requiring monitoring for nelfinavir and warfarin. Clinical use requires susceptibility confirmation and careful patient selection, particularly avoiding use in patients with moderate-to-severe pneumonia inappropriate for oral therapy.

At a glance

Mechanism of action

The label identifies azithromycin as a macrolide antibacterial drug but does not provide detailed mechanistic information regarding its molecular target or mode of action. The mechanism section references additional information that is not included in the provided text. The antibacterial activity is noted to be pH-related and appears reduced with decreasing pH, with extensive tissue distribution potentially relevant to clinical activity.

Approved indications

• Community-Acquired Pneumonia
• Pelvic Inflammatory Disease
• To reduce the development of drug-resistant bacteria and maintain the effectiveness of ZITHROMAX and other antibacterial drugs

Common side effects

• Headache
• Neutropenia
• Leukopenia
• Neutrophil count decreased
• Dizziness
• Nausea
• Diarrhoea
• Injection site pain
• Fatigue
• Muscle cramp
• Palpitations
• Cough

Drug interactions

• Nelfinavir
• Warfarin
• Digoxin, Colchicine, Phenytoin

Key clinical trials

• ARRET (PHASE4)

Primary sources

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