What is Azithromycin?

Azithromycin is a broad-spectrum macrolide antibiotic derived from erythromycin. It is distinguished by its unique pharmacokinetic properties, including an exceptionally long tissue half-life that allows for shorter treatment courses compared to other antibiotics. The drug works by binding to the 50S ribosomal subunit of susceptible bacteria, inhibiting RNA-dependent protein synthesis.

Indications

Azithromycin is indicated for mild to moderate infections caused by susceptible organisms, including community-acquired pneumonia, acute bacterial sinusitis, pharyngitis/tonsillitis, uncomplicated skin infections, acute otitis media, and sexually transmitted infections including chlamydia and gonorrhea.

Dosage

For most infections, the “Z-Pack” regimen is commonly used: 500 mg on day 1, followed by 250 mg on days 2-5. For community-acquired pneumonia: 500 mg on day 1, then 250 mg daily on days 2-5. For chlamydia: a single 1000 mg dose. Pediatric dosing varies by indication and weight.

Side Effects

Common side effects include diarrhea, nausea, abdominal pain, and vomiting. Rare but serious side effects include QT prolongation, hepatotoxicity, and allergic reactions. The medication should be used with caution in patients with hepatic impairment or known QT prolongation.