What is the recommended dosing of amoxicillin (amoxicillin) for a 5-year-old female patient with otitis media?

Amoxicillin Dosing for Otitis Media in a 5-Year-Old

For a 5-year-old child with acute otitis media, prescribe high-dose amoxicillin at 80-90 mg/kg/day divided into 2 doses daily for 5-10 days. 1, 2, 3

Dose Calculation

• Calculate the total daily dose by multiplying the child's weight in kilograms by 80-90 mg 1, 2
• For example, if the child weighs 18 kg (approximately 40 pounds), the total daily dose would be 1440-1620 mg/day 2
• Divide this total into 2 equal doses given approximately 12 hours apart (e.g., 720-810 mg twice daily for an 18 kg child) 1, 2
• The maximum daily dose is 4000 mg/day 1

Treatment Duration

• Treat for 5-10 days depending on age and severity, with 5 days being sufficient for children over 2 years with uncomplicated disease 2
• Children under 2 years should receive 10 days of therapy 3

Rationale for High-Dose Therapy

• High-dose amoxicillin (80-90 mg/kg/day) is the first-line treatment because it provides effective coverage against drug-resistant Streptococcus pneumoniae while maintaining safety, low cost, acceptable taste, and narrow microbiologic spectrum 1, 2
• High-dose therapy achieves middle ear fluid concentrations that exceed the minimum inhibitory concentration for intermediately resistant S. pneumoniae for a longer duration 3
• Approximately 87% of S. pneumoniae isolates are susceptible to high-dose amoxicillin 3

When to Use Amoxicillin-Clavulanate Instead

Switch to high-dose 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
• Coverage for beta-lactamase-producing Haemophilus influenzae or Moraxella catarrhalis is specifically desired 1, 2
• Use the 14:1 ratio formulation (amoxicillin to clavulanate), as it causes less diarrhea than other ratios 1, 3

Reassessment and Treatment Failure

• Reassess at 48-72 hours if symptoms fail to improve 2, 3
• Treatment failure is defined as worsening condition, persistence of symptoms beyond 48 hours, or recurrence within 4 days of completing therapy 2
• If no improvement occurs by 48-72 hours, switch to amoxicillin-clavulanate or ceftriaxone (50 mg IM or IV for 3 days) 1, 2
• Beta-lactamase-producing H. influenzae is the most common cause of treatment failure with amoxicillin monotherapy 2, 4

Pain Management

• Address pain management concurrently with antibiotic therapy during the first 24 hours using appropriate analgesics 2, 3

Common Pitfalls

• Avoid underdosing by using standard-dose amoxicillin (40-45 mg/kg/day) in areas with drug-resistant S. pneumoniae, as this provides inadequate coverage 1, 4
• Do not prescribe three-times-daily dosing, as twice-daily administration has equivalent efficacy and improves adherence 5
• Ensure accurate weight-based dosing rather than age-based dosing to achieve therapeutic levels 1, 2