What is the dose of azithromycin (Zithromax) for treating acute otitis media (ear infection)?

Azithromycin Dosing for Acute Otitis Media

For acute otitis media in children, the FDA-approved dose of azithromycin is 30 mg/kg as a single dose, or 10 mg/kg once daily for 3 days, or 10 mg/kg on day 1 followed by 5 mg/kg/day on days 2-5. 1

Dosing Options for Pediatric Patients

Azithromycin offers three FDA-approved dosing regimens for acute otitis media in children:

1. Single-dose regimen: 30 mg/kg as a single dose
2. 3-day regimen: 10 mg/kg once daily for 3 days
3. 5-day regimen: 10 mg/kg on day 1, followed by 5 mg/kg/day on days 2-5

Weight-Based Dosing Chart

For the single-dose (30 mg/kg) regimen:

• 5 kg (11 lbs): 3.75 mL (150 mg)
• 10 kg (22 lbs): 7.5 mL (300 mg)
• 20 kg (44 lbs): 15 mL (600 mg)
• 30 kg (66 lbs): 22.5 mL (900 mg)
• 40 kg (88 lbs): 30 mL (1200 mg)
• ≥50 kg (≥110 lbs): 37.5 mL (1500 mg) 1

Efficacy Considerations

Clinical studies have demonstrated that azithromycin is effective for treating acute otitis media:

• The single-dose (30 mg/kg) regimen showed an 88% clinical success rate at end-of-treatment and 85% at follow-up 1
• The 3-day regimen (10 mg/kg/day) demonstrated 83% clinical success at day 10 and 74% at day 24-28 1
• The 5-day regimen showed 88% clinical success at day 11 and 73% at day 30 1

Important Considerations and Caveats

1. First-line therapy: The American Academy of Pediatrics recommends high-dose amoxicillin (80-90 mg/kg/day) as the first-line treatment for acute otitis media in children 2

2. When to use azithromycin: Azithromycin should be considered in patients with:

   • Penicillin allergy
   • Compliance concerns (single-dose option)
   • Recent amoxicillin use within 30 days 2

3. Pathogen coverage: Azithromycin has excellent coverage against S. pneumoniae but may have reduced efficacy against H. influenzae, with bacteriologic eradication rates of 92% and 71% respectively 1

4. Resistance concerns: In regions with high macrolide resistance among S. pneumoniae, clinical success rates may be lower (67% for macrolide-resistant vs. 90% for macrolide-susceptible strains) 3

5. Administration: Azithromycin can be taken with or without food 1

6. Safety profile: Azithromycin typically has fewer gastrointestinal side effects compared to amoxicillin/clavulanate (11% vs. 20%) 4

Monitoring and Follow-up

• If symptoms persist after 48-72 hours of initial therapy, reassess the patient and consider switching to a second-line agent 2
• Persistent middle ear effusion is common after AOM resolution (60-70% at 2 weeks, 40% at 1 month) and does not require additional antibiotics 2

Special Populations

• Renal impairment: No dosage adjustment needed for GFR >10 mL/min; use caution in severe renal impairment 1
• Hepatic impairment: No specific dosing recommendations available 1

The single-dose regimen offers excellent compliance (99-100%) 3 and may be particularly valuable when adherence to multi-day regimens is a concern.