Please check your internet connection and try again.
# Azithromycin
## Overview
Azithromycin is a macrolide antibiotic effective against a wide range of bacteria. It is bacteriostatic, inhibiting bacterial protein synthesis.
## Primary Indications
* **Respiratory Tract Infections:** Community-acquired pneumonia, acute exacerbations of COPD, pharyngitis/tonsillitis (documented *Streptococcus pyogenes* infection).
* **Skin and Soft Tissue Infections:** Uncomplicated skin and skin structure infections.
* **Genital Ulcer Disease:** Chancroid.
* **Non-gonococcal urethritis and cervicitis:** Due to *Chlamydia trachomatis*.
* **Disseminated *Mycobacterium avium* complex (MAC) prophylaxis/treatment:** In patients with advanced HIV infection.
* **Pertussis:** Treatment and prophylaxis.
## Adult Dosing
* **Community-Acquired Pneumonia:** 500 mg on day 1, followed by 250 mg daily for days 2-5.
* **Acute Exacerbations of COPD:** 500 mg daily for 3 days.
* **Pharyngitis/Tonsillitis (documented *S. pyogenes*):** 500 mg once daily for 3 days OR 500 mg on day 1, followed by 250 mg daily for days 2-5.
* **Uncomplicated Skin and Skin Structure Infections:** 500 mg on day 1, followed by 250 mg daily for days 2-5.
* **Chancroid:** Single dose of 1 g.
* **Urethritis/Cervicitis (*Chlamydia trachomatis*):** Single dose of 1 g.
* **MAC Prophylaxis:** 1.2 g once weekly.
* **MAC Treatment:** 500 mg once daily, often in combination with other agents.
* **Pertussis:** 500 mg on day 1, followed by 250 mg daily for days 2-5.
## Pediatric Dosing
Dosing varies significantly by indication and weight. Refer to the most current pediatric dosing guidelines or product labeling for specific recommendations. A common regimen for acute otitis media is 10 mg/kg on day 1 (maximum 500 mg), followed by 5 mg/kg daily for days 2-5 (maximum 250 mg/day). Dosing for other indications like pneumonia or pharyngitis will differ.
## Dose Adjustments
No dose adjustment is necessary for renal or hepatic impairment, but caution is advised.
## Contraindications
* Hypersensitivity to azithromycin, erythromycin, any macrolide antibiotic, or any component of the formulation.
* History of cholestatic jaundice/hepatic dysfunction associated with prior azithromycin use.
## Adverse Effects
Common: Diarrhea, nausea, abdominal pain, vomiting.
Less Common: Dizziness, headache, rash, altered taste, elevated liver enzymes.
Serious (Rare): *Clostridioides difficile*-associated diarrhea, QT interval prolongation, severe allergic reactions (including anaphylaxis and Stevens-Johnson syndrome), hepatotoxicity.
## Key Drug Interactions
* **Antacids containing aluminum or magnesium:** May decrease azithromycin absorption. Administer azithromycin at least 1 hour before or 2 hours after antacids.
* **Warfarin:** May increase INR. Monitor INR closely.
* **Theophylline:** May increase theophylline levels. Monitor theophylline levels.
* **Cyclosporine:** May increase cyclosporine levels. Monitor cyclosporine levels.
* **Digoxin:** May increase digoxin levels. Monitor digoxin levels.
* **Ergot alkaloids:** Concomitant use is not recommended due to potential ergotism.
* **CYP3A4 substrates (e.g., certain statins, calcium channel blockers):** Azithromycin is a weak inhibitor of CYP3A4. Monitor for increased concentrations of co-administered drugs.
## Monitoring
* Monitor for signs and symptoms of hypersensitivity reactions.
* Monitor for *C. difficile*-associated diarrhea.
* Monitor liver function tests if hepatic impairment is suspected or with prolonged treatment.
* Monitor ECG for QT prolongation, especially in patients with risk factors (e.g., electrolyte abnormalities, concomitant QT-prolonging drugs).
## Clinical Pearls
* Azithromycin's long half-life allows for once-daily dosing and shorter treatment durations for some indications compared to other antibiotics.
* Can be taken with or without food. However, administration with food may decrease nausea.
* Ensure adequate hydration.
* Counsel patients on completing the full course of therapy, even if symptoms improve.
***
*This information is intended as a quick reference and does not replace professional medical advice. Always consult the most current prescribing information and relevant clinical guidelines for complete details before making any treatment decisions.*
