Prescription ·Strong evidence ·Reviewed May 2026
A macrolide antibiotic with a broad spectrum of activity against gram-positive, some gram-negative, and atypical organisms (Mycoplasma, Chlamydia, Legionella). The 5-day 'Z-Pack' course is one of the most commonly prescribed antibiotic regimens. Used for community-acquired pneumonia, acute bacterial exacerbations of COPD, sinusitis, pharyngitis (in penicillin-allergic patients), sexually transmitted infections (chlamydia, gonorrhea as adjunct), and traveler's diarrhea.
The bottom line
Evidence rating strong. Most-documented uses: treats community-acquired pneumonia, treats acute bacterial sinusitis, treats acute exacerbation of copd. 10 sources indexed (2015–2025), with 2 interaction records on file.
Core mechanism
Binds to the 50S ribosomal subunit of susceptible bacteria, specifically the 23S rRNA of the peptidyl transferase center. This blocks translocation of peptides during translation, inhibiting bacterial protein synthesis. Azithromycin is bacteriostatic at usual concentrations but may be bactericidal at high local concentrations. It concentrates extensively in tissues and phagocytes, achieving intracellular concentrations 10-100x higher than plasma.
Oral bioavailability approximately 37%. Tablets can be taken with or without food. Oral suspension should be taken on an empty stomach (1 hour before or 2 hours after meals). High tissue penetration and prolonged tissue half-life.
Nutrients this medication can lower over time, and what to replace.
Broad-spectrum antibiotic exposure can suppress gut bacteria that synthesize menaquinones, lowering vitamin K availability in susceptible patients.
Probiotic supplementation during azithromycin therapy reduces antibiotic-associated diarrhea and helps preserve gut microbiome diversity, which can be significantly disrupted by macrolide exposure.
Recommendation: Take probiotics throughout your azithromycin course, separated by at least 2 hours from each antibiotic dose. Continue for at least 1 week after the antibiotic ends.
Saccharomyces boulardii reduces antibiotic-associated diarrhea during azithromycin therapy and is unaffected by the antibiotic because it is a yeast.
Recommendation: Take Saccharomyces boulardii throughout your azithromycin course. Timing flexibility is greater than with bacterial probiotics. Continue for at least 1 week after the antibiotic ends.
Numbered references. Citations throughout the page link here.
Methaneethorn J, Jiao Z, AlEjielat R et al.. Influential predictors of azithromycin pharmacokinetics: a systematic review of population pharmacokinetics. Annals of medicine. 2025
Ukkonen RM, Renko M, Kuitunen I. Azithromycin for acute bronchiolitis and wheezing episodes in children - a systematic review with meta-analysis. Pediatric research. 2024
Meta-analysis of RCTs found azithromycin did not reduce mortality, hospitalization, or symptom resolution in COVID-19 patients compared to standard of care or placebo, and was associated with increased antibiotic resistance.
Systematic review found azithromycin had a generally favorable safety profile in children with overall adverse event rates comparable to other antibiotics; gastrointestinal effects (vomiting, diarrhea) were the most common side effects.
Tian BP, Xuan N, Wang Y et al.. The efficacy and safety of azithromycin in asthma: A systematic review. Journal of cellular and molecular medicine. 2019
Smith C, Egunsola O, Choonara I et al.. Use and safety of azithromycin in neonates: a systematic review. BMJ open. 2015
Nag K, Tripura K, Datta A et al.. Effect of Hydroxychloroquine and Azithromycin Combination Use in COVID-19 Patients - An Umbrella Review. Indian journal of community medicine : official publication of Indian Association of Preventive & Social Medicine. 2024
This page is educational. Do not start, stop, or change a supplement or medication based on it without checking with a qualified healthcare professional.
Use this with your stack
Add it to your stack, see how it interacts with everything else you take, and get a Stack Score that updates the moment it does.
NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.
NutriStack