Medscape - Infection-specific dosing for Zithromax (azithromycin), frequency-based adverse effects, comprehensive interactions, contraindications, pregnancy & lactation schedules, and cost. No fluff, no fear-mongering — just clear, calm guidance on taking Zithromax. When it works fast, when to watch for side effects, why you shouldn’t skip the last pill, and what no one mentions about your gut afterward. Overview: Azithromycin is an antibiotic that is used to treat certain bacterial infections. It works by stopping certain types of bacteria from making proteins they need to grow and multiply. Azithromycin is a semi-synthetic antibiotic of the azalide subclass, derived from the classical macrolide erythromycin by the insertion of a methylated nitrogen atom into the 14-membered macrolactone ring, expanding it to a 15-membered ring. Zithromax or Z-PAK (azithromycin) is a semi-synthetic macrolide antibiotic used for treating bacterial infection. Learn about dosages, side effects, drug interaction, warnings, and more. ZITHROMAX (azithromycin) for injection is a macrolide antibacterial drug indicated for the treatment of patients with infections caused by susceptible strains of the designated microorganisms in. What is Zithromax Z-Pak? Zithromax Z-Pak is used to treat many different types of infections caused by bacteria, including infections of the lungs, sinus, throat, tonsils, skin, urinary tract, cervix, or genitals. Zithromax Z-Pak may also be used for purposes not listed in this medication guide. Zithromax is an antibiotic that fights bacteria. Zithromax is used to treat many different types of infections caused by bacteria, such as respiratory infections, skin infections, ear infections, and sexually transmitted diseases. What it is: Azithromycin (Zithromax, Z-Pak)—macrolide antibiotic for community-acquired pneumonia, certain STIs, sinusitis, and some skin infections. Typical dose: Z-Pak: 500 mg on day 1, then 250 mg days 2–5. ZITHROMAX (azithromycin) is a macrolide antibacterial drug indicated for the treatment of patients with mild to moderate infections caused by susceptible strains of the designated microorganisms in the specific conditions listed below.