Azithromycin pills in Europe, with brand name Sumamed. Azithromycin, sold under the brand names Zithromax (in oral form) and Azasite (as an eye drop), is an antibiotic medication used to treat several bacterial infections. [9]. Azithromycin 5 Day Dose Pack 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. Azithromycin 5 Day Dose Pack may also be used for purposes not listed in this medication guide. It contains six 250 mg tablets of azithromycin taken over 5 days. Z-Paks can treat several bacterial infections, ranging from pneumonia to skin infections. Common Z-Pak side effects include diarrhea, nausea, and stomach pain. Z-Paks are widely available as a lower-cost generic. Take this medication by mouth with a full glass of water. Take it as directed on the prescription label. You can take it with food or on an empty stomach. If it upsets your stomach, take it with food. Take your medication at regular intervals. Do not take your medication more often than directed. Quick Answer: Azithromycin — sold as Zithromax or the Z-Pak — is a macrolide antibiotic prescribed to treat bacterial infections including pneumonia, chlamydia, strep throat, and sinusitis. How does a Z‑Pak work so quickly? A Z‑Pak gives you a strong initial dose—two tablets on Day 1 and one tablet each on Days 2–5. Even though you stop after five days, the medication keeps working long after because it stays active in the body for over two days at a time. 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. What is a Z-Pak? A Z-Pak contains the active ingredient azithromycin. It is an antibiotic used to treat certain types of bacterial infections, such as strep throat, sinus infections, middle ear infections, and community-acquired pneumonia. It does not work for viral infections like the cold or flu. Z-Pak is a prescription antibiotic with six 250 mg tablets of azithromycin in a blister pack. It can treat several bacterial infections, including strep throat, ear infections, and pneumonia. 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..