What is the appropriate amoxicillin (Amoxil) dosage for treating acute otitis media in a child weighing 17.2 kg?

Amoxicillin Dosing for Acute Otitis Media in a 17.2 kg Child

For a child weighing 17.2 kg with acute otitis media, prescribe high-dose amoxicillin at 80-90 mg/kg/day divided into two doses, which equals 1376-1548 mg total daily dose, or approximately 688-774 mg per dose given every 12 hours for 10 days. 1, 2, 3

Exact Dose Calculation

• Multiply the child's weight (17.2 kg) by 80-90 mg to determine the total daily dose: this yields 1376-1548 mg per day. 3
• Divide this total into two equal doses given every 12 hours: prescribe approximately 700-775 mg twice daily (rounding to convenient suspension volumes such as 700 mg or 750 mg twice daily). 1, 3
• A practical approach is to prescribe 750 mg twice daily, which provides approximately 87 mg/kg/day and falls within the recommended high-dose range. 3

Treatment Duration Based on Age

• This child requires a full 10-day course of therapy, as the American Academy of Pediatrics recommends 10 days for children under 2 years regardless of symptom severity, with treatment failure rates of only 4% with antibiotics versus 23% with placebo by day 4-5. 1
• Children over 2 years with uncomplicated AOM may be treated for 5-7 days, but extend to 10 days for severe symptoms or bilateral disease. 2, 3

Rationale for High-Dose Therapy

• High-dose amoxicillin (80-90 mg/kg/day) achieves adequate middle ear fluid concentrations against drug-resistant Streptococcus pneumoniae, with 87% susceptibility compared to 83% for standard dosing. 1
• Standard-dose amoxicillin (40-45 mg/kg/day) provides inadequate coverage for resistant organisms and should not be used in children under 2 years. 1, 3
• The number needed to treat (NNT) is 3 for children younger than 2 years with bilateral AOM, with treatment failure rates dropping from 60% with placebo to 23% with antibiotics. 1

Clinical Monitoring and When to Switch

• Reassess the patient at 48-72 hours if symptoms do not improve or worsen. 1, 2, 3
• If treatment failure occurs (persistent fever, worsening otalgia, or new symptoms), escalate to high-dose amoxicillin-clavulanate at 90 mg/kg/day of the amoxicillin component with 6.4 mg/kg/day clavulanate. 1, 3
• Amoxicillin-clavulanate provides coverage against β-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis. 1

Pain Management

• Address pain management concurrently with antibiotic therapy during the first 24 hours using acetaminophen or ibuprofen, regardless of antibiotic choice. 1, 3
• Persistent middle ear effusion without acute symptoms is common (60-70% at 2 weeks) and does not require additional antibiotics. 1

Critical Pitfalls to Avoid

• Do not underdose: Failure to use high-dose amoxicillin (80-90 mg/kg/day) leads to treatment failures, especially with resistant S. pneumoniae. 3
• Do not use macrolides (azithromycin, clarithromycin) as first-line therapy, as they have only 20-25% effectiveness against major AOM pathogens. 1
• Do not prescribe a 7-day course for children under 2 years; they require 10 days regardless of severity. 1
• Always recalculate dosing based on current weight, not age-based estimates. 3