What is the recommended dose of amoxicillin (amoxicillin) for a 12-year-old patient weighing 63.8kg with otitis media?

Amoxicillin Dosing for 12-Year-Old with Otitis Media

For a 12-year-old weighing 63.8 kg with otitis media, prescribe amoxicillin 2000 mg twice daily (4000 mg/day total) for 10 days. 1, 2

Dose Calculation and Maximum Limits

• The American Academy of Pediatrics recommends high-dose amoxicillin at 80-90 mg/kg/day divided into two doses for acute otitis media 3, 1
• Weight-based calculation for this patient would be 5,104-5,742 mg/day, but the maximum safe dose is capped at 4000 mg/day (2000 mg twice daily), which is the standard adult maximum 1, 2
• This maximum dose of 4000 mg/day should never be exceeded, even when weight-based calculations suggest higher amounts 1, 2
• The 4000 mg/day maximum represents approximately 63 mg/kg/day for this patient, which still provides adequate coverage against drug-resistant Streptococcus pneumoniae 2

Treatment Duration and Administration

• Administer 2000 mg twice daily (every 12 hours) for 10 days 1, 2
• Amoxicillin can be taken without regard to meals, though administration with food may improve gastrointestinal tolerability 1
• The patient is no longer contagious after 24 hours of antibiotic therapy 1

Pain Management

• Address pain management concurrently with antibiotic therapy, especially during the first 24 hours 1, 4
• Pain control should be provided regardless of antibiotic choice 2, 4

When to Reassess and Switch Therapy

• Reassess at 48-72 hours if symptoms worsen or fail to improve 1, 4
• If treatment fails, switch to high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate, maximum 4000 mg/day amoxicillin) 1, 2, 4
• For persistent failure after amoxicillin-clavulanate, consider intramuscular ceftriaxone 50 mg/kg/day for 3-5 days 2

First-Line Therapy Exceptions

• Use amoxicillin-clavulanate as first-line instead of amoxicillin if the patient received amoxicillin in the previous 30 days or has concurrent purulent conjunctivitis (otitis-conjunctivitis syndrome) 3, 1

Common Pitfalls to Avoid

• Do not use standard-dose amoxicillin (40-45 mg/kg/day) in areas with >10% penicillin-nonsusceptible S. pneumoniae 1
• Do not exceed 2000 mg per single dose or 4000 mg/day total, even when weight-based calculations suggest higher doses 1, 2
• Do not use amoxicillin-clavulanate as first-line therapy unless the patient received amoxicillin in the previous 30 days or has otitis-conjunctivitis syndrome 1

Rationale for High-Dose Therapy

• High-dose amoxicillin achieves adequate middle ear fluid concentrations against drug-resistant Streptococcus pneumoniae, with approximately 87% of S. pneumoniae isolates susceptible to high-dose therapy versus only 83% for standard-dose 2
• The current standard-dose recommendation of 40 mg/kg/day is inadequate to effectively eradicate resistant Streptococcus pneumoniae 5