Amoxicillin Dosage for Otitis Media in a 6-Year-Old Child
The correct total daily dose of amoxicillin for a 20 kg child with otitis media is 1600 mg per day (80 mg/kg/day × 20 kg), divided into two doses of 800 mg each. 1
Dosage Calculation
- Weight of child: 20 kg
- Recommended dosage: 80 mg/kg/day
- Calculation: 80 mg/kg/day × 20 kg = 1600 mg/day
- Administration: Divided BID (twice daily) = 800 mg per dose
Evidence-Based Rationale
The American Academy of Pediatrics (AAP) and American Academy of Family Physicians (AAFP) guidelines specifically recommend amoxicillin at a dosage of 80-90 mg/kg/day for the treatment of acute otitis media 1. This higher dosage is based on microbiologic studies and expert opinion, with a preponderance of benefit over risk.
Why This Dosage?
- The higher dosage (80-90 mg/kg/day) is recommended to effectively treat potentially resistant pneumococci
- Amoxicillin remains the first-line therapy for AOM because it is:
- Effective against susceptible and intermediate-resistant pneumococci
- Safe with an acceptable side effect profile
- Cost-effective
- Has a narrow microbiologic spectrum
Administration Considerations
- The total daily dose should be divided into two equal doses (BID)
- Medication should be given at the start of a meal to minimize gastrointestinal intolerance 2
- Treatment should continue for a minimum of 48-72 hours beyond symptom resolution 2
Important Clinical Considerations
- If the patient fails to respond within 48-72 hours, reassessment is necessary 1
- Treatment should continue for at least 10 days if the infection is caused by Streptococcus pyogenes to prevent acute rheumatic fever 2
- Pain management should be addressed regardless of antibiotic use 1
Potential Pitfalls to Avoid
- Underdosing: Using the standard 40 mg/kg/day dosage is inadequate for resistant Streptococcus pneumoniae, particularly during viral coinfection 3
- Incorrect frequency: While once or twice daily dosing has been shown to be comparable to three times daily dosing 4, the guidelines specifically recommend BID dosing for the 80 mg/kg/day regimen
- Failure to reassess: If symptoms don't improve within 48-72 hours, the diagnosis should be reconsidered or the antibiotic changed 1
Remember that while amoxicillin-clavulanate may be considered for certain cases (such as treatment failure or suspected beta-lactamase producing organisms), standard amoxicillin remains the first-line agent for uncomplicated otitis media in children 1, 5.