Amoxicillin Dosing for a 7-Year-Old with Acute Otitis Media
For a 7-year-old child with acute otitis media, prescribe high-dose amoxicillin at 80-90 mg/kg/day divided into two doses given every 12 hours for 10 days. 1, 2
Calculating the Exact Dose
- Multiply the child's weight in kilograms by 80-90 mg to determine the total daily dose, then divide this into two equal doses administered every 12 hours. 2
- For example, a 7-year-old weighing 23 kg (approximately 50 lbs) would receive 1,840-2,070 mg total daily, or 920-1,035 mg twice daily 2
- Twice-daily dosing is equally effective as three-times-daily administration and significantly improves adherence 2
Duration of Treatment
- Complete a full 10-day course of therapy. 1, 2
- While children under 2 years absolutely require 10 days regardless of severity, children 6 years and older with mild-to-moderate disease could potentially receive shorter courses, but 10 days remains the standard recommendation for optimal outcomes 2
Rationale for High-Dose Therapy
- High-dose amoxicillin achieves adequate middle ear fluid concentrations against drug-resistant Streptococcus pneumoniae, with 87% susceptibility compared to 83% for standard dosing 2
- This dosing provides effective coverage against the most common AOM pathogens while maintaining excellent safety, low cost, acceptable taste, and narrow microbiologic spectrum 1
- Standard-dose amoxicillin (40-45 mg/kg/day) should not be used, as it provides inadequate coverage for resistant organisms 2
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
- The child received amoxicillin in the previous 30 days 1, 3
- Concurrent purulent conjunctivitis is present (otitis-conjunctivitis syndrome) 1, 3
- Coverage for β-lactamase-producing Haemophilus influenzae or Moraxella catarrhalis is specifically desired 1
Clinical Monitoring and Treatment Failure
- Reassess at 48-72 hours if symptoms do not improve or worsen. 2
- Address pain management with analgesics regardless of antibiotic choice 2
- If treatment fails after 48-72 hours on amoxicillin alone, escalate to high-dose amoxicillin-clavulanate 1, 2
- Persistent middle ear effusion without acute symptoms is common (60-70% at 2 weeks) and does not require additional antibiotics 2
Critical Pitfalls to Avoid
- Never use macrolides (azithromycin, clarithromycin) as first-line therapy—they have only 20-25% effectiveness against major AOM pathogens 2
- Do not prescribe standard-dose amoxicillin, as it is inadequate for resistant organisms 2
- Do not stop treatment early even if symptoms resolve, as incomplete eradication increases resistance risk 2