Medscape - Infection-specific dosing for Zithromax (azithromycin), frequency-based adverse effects, comprehensive interactions, contraindications, pregnancy & lactation schedules, and cost information. Description Azithromycin is used to treat certain bacterial infections in many different parts of the body. This medicine may mask or delay the symptoms of syphilis. It is not effective against syphilis infections. Azithromycin belongs to the class of drugs known as macrolide antibiotics. It works by killing bacteria or preventing their growth. However, this medicine will not work for colds. Azithromycin Dosing and Treatment Duration Azithromycin dosing varies significantly by indication, with the most common adult regimen being 500 mg on day 1 followed by 250 mg daily on days 2-5 for respiratory infections, while sexually transmitted infections typically require a single 1-gram dose. 1 Find patient medical information for Azithromycin (Zithromax, Z-Pak, Zmax) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings Complete guide to azithromycin dosing calculator for pediatric and adult patients. Professional tool for accurate antibiotic dose calculations with safety features. Read on for Z-Pak dosage information, including typical dosage, adjustments for health conditions, and what to do if you miss a dose. Azithromycin is used to treat certain bacterial infections. Find out what the recommended dosages are, how to take the drug, and more. NHS medicines information on dosage for azithromycin, how to take it and what to do if you miss a dose or take too much. Detailed Azithromycin dosage information for adults and children. Includes dosages for Bacterial Infection, Sinusitis, Bronchitis and more; plus renal, liver and dialysis adjustments.