What is the recommended dose of amoxicillin (amoxicillin) for a child with otitis media weighing 43 pounds?

Amoxicillin Dosing for Otitis Media in a 43-Pound Child

For a child weighing 43 pounds (19.5 kg) with acute otitis media, prescribe amoxicillin 80-90 mg/kg/day divided into 2 doses, which equals approximately 780-880 mg twice daily (or 390-440 mg per dose). 1

Dose Calculation

• Child's weight: 43 pounds = 19.5 kg
• Recommended dosing: 80-90 mg/kg/day 1
• Total daily dose: 1560-1755 mg/day
• Divided into 2 doses: 780-880 mg twice daily 1

Rationale for High-Dose Amoxicillin

High-dose amoxicillin (80-90 mg/kg/day) is the first-line treatment for acute otitis media because it provides effective coverage against drug-resistant Streptococcus pneumoniae while maintaining safety, low cost, acceptable taste, and narrow microbiologic spectrum. 1

• The American Academy of Pediatrics (AAP) and American Academy of Family Physicians (AAFP) specifically recommend this higher dosing to address pneumococcal strains with intermediate resistance to penicillin 1
• This dosing achieves adequate middle ear fluid concentrations against susceptible and intermediate-resistant pneumococci 1

Dosing Frequency: Twice Daily vs Three Times Daily

Amoxicillin can be administered twice daily rather than three times daily with equivalent clinical efficacy, which may improve adherence. 2, 3

• A Cochrane review demonstrated that once or twice daily dosing showed comparable clinical cure rates to three times daily dosing (RR 1.03,95% CI 0.99-1.07) 2
• A 2023 study found 92% favorable outcomes with twice-daily dosing versus 95% with three-times-daily dosing (p=0.25), with twice-daily dosing associated with fewer family-reported scheduling difficulties 3
• The WHO Pocket Book recommends 40 mg/kg twice daily for acute otitis media in resource-limited settings, though this represents a lower dose than current U.S. guidelines 1

Practical Prescribing

For this 19.5 kg child, practical dosing options include:

• 800 mg twice daily (approximately 82 mg/kg/day) - achievable with standard amoxicillin suspensions
• Duration: 5-10 days depending on age and severity 1

When to Consider Alternatives

Switch to amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate) if: 1

• The child received amoxicillin in the previous 30 days 1
• Concurrent purulent conjunctivitis is present (otitis-conjunctivitis syndrome) 1
• Coverage for beta-lactamase-producing Haemophilus influenzae or Moraxella catarrhalis is desired 1, 4

Reassessment Criteria

Reassess the patient at 48-72 hours if symptoms fail to improve. 1

• The child should stabilize within 24 hours and begin improving during the second 24-hour period 1
• If no improvement occurs by 48-72 hours, consider treatment failure and switch to amoxicillin-clavulanate or ceftriaxone 1
• Bacteriologic studies show that beta-lactamase-producing organisms (particularly H. influenzae) are the predominant cause of amoxicillin failure 4

Important Caveats

• High-dose amoxicillin demonstrates good overall clinical efficacy despite bacteriologic persistence in some cases, with 82% eradication rates in culture-positive studies 4
• The risk-benefit profile favors high-dose amoxicillin even in communities with lower prevalence of drug-resistant pneumococcus, as the probability of infection with strains requiring higher doses remains clinically significant 5
• Pain management should be addressed concurrently with antibiotic therapy during the first 24 hours 1