Z-Pak Contains Azithromycin
The Z-Pak contains azithromycin, a macrolide antibiotic (specifically an azalide subclass of macrolides). 1
What is Azithromycin?
Azithromycin is derived from erythromycin but differs chemically by incorporating a methyl-substituted nitrogen atom into the lactone ring, creating a 15-membered ring structure rather than the typical 14-membered macrolide ring 1. This structural modification classifies it as an azalide—the first of its class.
Formulation Details
The Z-Pak formulation contains:
- Active ingredient: Anhydrous azithromycin (250 mg or 500 mg per tablet)
- Form: White, film-coated, oval-shaped biconvex tablets
- Inactive ingredients: Microcrystalline cellulose, corn starch, croscarmellose sodium, magnesium trisilicate, magnesium stearate, colloidal silicon dioxide, hydroxypropyl cellulose, sodium lauryl sulfate, hypromellose, titanium dioxide, and polyethylene glycol 1
Standard Dosing Regimen
The typical Z-Pak dosing for adults is 500 mg on day 1, followed by 250 mg daily on days 2-5 2. This convenient once-daily dosing schedule for 5 days is one of the distinguishing features that made this formulation popular in clinical practice.
For pediatric patients, dosing varies by age and weight, with infants <6 months receiving 10 mg/kg daily for 5 days, and children ≥6 months receiving 10 mg/kg (maximum 500 mg) on day 1, then 5 mg/kg daily (maximum 250 mg) on days 2-5 2.