What is the recommended dose of amoxicillin (amoxicillin) for an 80-pound child with an ear infection?

Amoxicillin Dosing for Ear Infection in an 80-Pound Child

For an 80-pound (36 kg) child with acute otitis media, prescribe amoxicillin 80-90 mg/kg/day divided into two doses, which equals approximately 1440-1620 mg twice daily (or practically, 1500 mg twice daily). 1, 2, 3

Dose Calculation

• An 80-pound child weighs approximately 36 kg 2
• The recommended high-dose amoxicillin is 80-90 mg/kg/day divided into 2 doses 1, 2, 4
• This calculates to 2880-3240 mg total daily dose, or 1440-1620 mg per dose given twice daily 1, 2
• A practical prescription would be 1500 mg twice daily (approximately 83 mg/kg/day) 2
• The maximum daily dose is 4000 mg/day, so this dosing is well within safe limits 1, 3

Rationale for High-Dose Therapy

High-dose amoxicillin is the first-line treatment for acute otitis media because it provides effective coverage against drug-resistant Streptococcus pneumoniae while maintaining excellent safety, low cost, acceptable taste, and narrow microbiologic spectrum. 1, 2, 4

• High-dose amoxicillin achieves middle ear fluid levels that exceed the minimum inhibitory concentration (MIC) for intermediately resistant S. pneumoniae (penicillin MICs 0.12-1.0 μg/mL) and many highly resistant serotypes (penicillin MICs ≥2 μg/mL) 1
• Standard-dose amoxicillin (40-45 mg/kg/day) is inadequate to effectively eradicate resistant S. pneumoniae, particularly during viral coinfection 5
• The predominant pathogens in acute otitis media are S. pneumoniae, H. influenzae, and M. catarrhalis 1, 2, 4

Treatment Duration

• Treat for 10 days in children under 2 years of age or those with severe symptoms 1, 2
• For children 2 years and older with mild-to-moderate symptoms, 5-7 days may be sufficient 2
• Continue treatment for a minimum of 48-72 hours beyond symptom resolution 3

When to Switch to Alternative Therapy

Switch to amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses) if: 1, 2

• The child received amoxicillin in the previous 30 days 1, 2
• Concurrent purulent conjunctivitis is present 1, 2
• No improvement occurs after 48-72 hours of high-dose amoxicillin therapy 1, 2, 4
• Coverage for beta-lactamase-producing H. influenzae or M. catarrhalis is specifically desired 1, 6

Administration and Compliance

• Administer amoxicillin at the start of a meal to minimize gastrointestinal intolerance 3
• Once or twice daily dosing is as effective as three times daily dosing and may improve compliance 7
• For this 36 kg child, twice-daily dosing (1500 mg every 12 hours) is appropriate and convenient 1, 2, 7

Reassessment Criteria

Reassess the patient at 48-72 hours if symptoms fail to improve. 1, 2, 4

• Treatment failure is defined as worsening condition, persistence of symptoms beyond 48 hours, or recurrence within 4 days of completing therapy 2
• Beta-lactamase-producing H. influenzae is the most common cause of treatment failure with amoxicillin monotherapy 2, 6
• If treatment failure occurs, switch to amoxicillin-clavulanate or consider ceftriaxone 1, 2

Pain Management

Address pain management concurrently with antibiotic therapy during the first 24 hours using appropriate analgesics (acetaminophen or ibuprofen). 2, 4

Common Pitfalls to Avoid

• Do not use standard-dose amoxicillin (40-45 mg/kg/day) as it is inadequate for resistant S. pneumoniae 1, 5, 8
• Do not prescribe the 875 mg tablet formulation, as this would underdose this child (only 1750 mg/day total) 3
• Do not use amoxicillin-clavulanate as first-line therapy unless specific indications are present, as it increases diarrhea risk 1
• Ensure adequate hydration and monitor for adverse effects, though high-dose amoxicillin does not significantly increase adverse events compared to standard dosing 8