Azithromycin 5 Day Dose Pack typically takes at least five days to fully work, but it can start to relieve your sore throat and other symptoms on the first day you take it. The typical Z-Pak dosage for adults is 2 tablets on the first day of treatment, followed by 1 tablet on Days 2 to 5. Children’s azithromycin dosages are based on body weight and the infection being treated. A 5 day pack of azithromycin, known as the Z-Pak, is an antibiotic that treats bacterial infections. Learn its uses, side effects, and how it works. Azithromycin is a macrolide antibiotic packaged as the Z-Pack, containing six 250mg tablets designed for a specific five-day treatment regimen. This antibiotic works by inhibiting bacterial protein synthesis, making it effective against a wide range of gram-positive and some gram-negative bacteria. Azithromycin 5 Day Dose Pack: side effects, dosage, interactions, FAQs, reviews. Used for: babesiosis, bacterial endocarditis prevention, bacterial infection, bartonellosis, and more. Azithromycin is an oral antibiotic used for a wide range of bacterial infections. When taken as a five day regimen, a ‘Z-Pak’ is often used to target bacteria associated with upper respiratory tract infections, including community acquired pneumonia. The standard Z-pack (azithromycin) dosage for adults with common bacterial infections is 500 mg on day 1, followed by 250 mg once daily on days 2 through 5, with specific variations based on the type of infection being treated. 1 Marcus, 34, was prescribed a 5-day Z-Pak for a chest infection. By Day 3, he felt significantly better and stopped taking the remaining pills. Three weeks later, his infection came back — worse than before. His doctor explained why: azithromycin doesn’t stop working when you do. The dose is usually 12 milligrams (mg) per kilogram (kg) of body weight once a day for 5 days. Children younger than 2 years of age—Use and dose must be determined by your doctor. 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..