What is the recommended dose of Azithromycin (macrolide antibiotic) for a 30 kg female child?

Azithromycin Dosing for a 30 kg Female Child

For a 30 kg female child, administer azithromycin 300 mg (10 mg/kg) once daily on day 1, followed by 150 mg (5 mg/kg) once daily on days 2-5 for most respiratory tract infections. 1, 2

Standard Dosing Regimens by Indication

Community-Acquired Pneumonia

• 10 mg/kg as a single dose on day 1, followed by 5 mg/kg once daily on days 2-5 1, 2
• For a 30 kg child: 300 mg on day 1, then 150 mg daily for days 2-5 1
• Total treatment course: 22.5 mL of 200 mg/5 mL suspension, delivering 900 mg total 2

Acute Otitis Media

Three acceptable regimens exist 2:

• 5-day regimen (preferred): 10 mg/kg on day 1, then 5 mg/kg on days 2-5 1, 2
• 3-day regimen: 10 mg/kg once daily for 3 days (total 900 mg) 2
• Single-dose regimen: 30 mg/kg as a single dose (900 mg total) 2

Acute Bacterial Sinusitis

• 10 mg/kg once daily for 3 days 2
• For a 30 kg child: 300 mg daily for 3 days 1

Pharyngitis/Tonsillitis (Group A Streptococcal)

• 12 mg/kg once daily for 5 days 2, 3
• For a 30 kg child: 360 mg daily for 5 days 3
• This higher dose (total 60 mg/kg) is necessary for adequate GABHS eradication 3

Formulation Selection

For a 30 kg child, use the 200 mg/5 mL oral suspension 2:

• Day 1: 7.5 mL (1½ teaspoons) = 300 mg 1, 2
• Days 2-5: 3.75 mL (¾ teaspoon) = 150 mg 1, 2

Critical Dosing Considerations

Maximum Doses

• Do not exceed adult doses regardless of weight 1, 2
• For standard 5-day regimen in children ≥50 kg: use adult dosing of 500 mg day 1, then 250 mg days 2-5 2

Administration

• Can be taken with or without food 2
• If vomiting occurs within 30 minutes of a 30 mg/kg single dose, re-dosing at the same total dose has been studied in clinical trials, though safety data are limited 2

Special Populations

• Renal impairment: No dosage adjustment needed for GFR >10 mL/min; exercise caution if GFR <10 mL/min 2
• Hepatic impairment: No established dosing recommendations; use with caution 2

Common Pitfalls to Avoid

Underdosing in Pharyngitis

• The standard 10 mg/kg day 1, then 5 mg/kg days 2-5 regimen results in higher recurrence rates for streptococcal pharyngitis compared to penicillin 3
• Always use 12 mg/kg daily for 5 days (total 60 mg/kg) for proven GABHS pharyngitis 3

Inappropriate Indication Selection

• Azithromycin should only be used for documented bacterial infections, not viral pharyngitis 3
• For suspected atypical pathogens (Mycoplasma, Chlamydophila), azithromycin is preferred over beta-lactams 1, 4

Duration Errors

• The 5-day regimen provides therapeutic tissue concentrations for several days after the last dose due to azithromycin's unique pharmacokinetics 5, 6
• Do not extend treatment beyond recommended duration unless clinically indicated, as this promotes resistance 1

Tolerability Profile

• Adverse events occur in approximately 9% of pediatric patients, predominantly mild-to-moderate gastrointestinal complaints 7
• Better tolerated than amoxicillin/clavulanic acid but may cause more GI effects than phenoxymethylpenicillin 5
• Higher doses (20-30 mg/kg/day) are associated with increased adverse effects but remain generally well-tolerated 7