Amoxicillin Dosing for Otitis Media in a 54 kg Pediatric Patient
For a 54 kg pediatric patient with otitis media, prescribe amoxicillin 2000 mg twice daily (total 4000 mg/day) for 7 days, which represents the maximum safe adult dose and falls within the high-dose range of 80-90 mg/kg/day recommended for severe or resistant infections. 1
Dosing Rationale
The weight-based calculation (80-90 mg/kg/day) would yield 4320-4860 mg/day for this patient, but the total daily dose must be capped at the standard adult maximum of 4000 mg/day (2000 mg twice daily). 1 This maximum represents approximately 74 mg/kg/day for a 54 kg patient, which still provides adequate coverage against drug-resistant Streptococcus pneumoniae and other common otitis media pathogens. 1, 2
High-Dose vs Standard-Dose Selection
High-dose amoxicillin (80-90 mg/kg/day) is specifically indicated for patients with risk factors for resistant organisms, including recent antibiotic use (within 4-6 weeks), daycare attendance, age under 2 years, or moderate-to-severe disease. 3, 2
For uncomplicated cases in children ≥2 years without recent antibiotic exposure, standard-dose amoxicillin (45 mg/kg/day) may be sufficient, which would be 2430 mg/day for this patient—still capped at 2000 mg twice daily for practical dosing. 3
Given the 7-day treatment course specified (rather than 10 days), this suggests either mild-to-moderate disease in an older child or a shortened course decision—in which case the higher dose provides better coverage. 3, 1
Practical Prescribing
Administer as 2000 mg (four 500 mg capsules) twice daily, taken every 12 hours. 1
The 7-day duration is acceptable for older children with uncomplicated otitis media, though 10 days is preferred for children under 6 years or those with severe symptoms. 1
Reassess at 48-72 hours if symptoms do not improve or worsen. 3, 1, 2
Alternative Therapy for Treatment Failure
If the patient fails to respond within 48-72 hours, switch to high-dose amoxicillin-clavulanate (90 mg/6.4 mg/kg/day of amoxicillin/clavulanate components, maximum 4000 mg/day amoxicillin). 3, 1 This would be 2000 mg amoxicillin component twice daily using the appropriate formulation. 3
For persistent failure after amoxicillin-clavulanate, consider intramuscular ceftriaxone 50 mg/kg/day (maximum 2700 mg for this patient) for 3-5 days. 3, 1
Beta-lactamase-producing Haemophilus influenzae is the predominant pathogen in amoxicillin failures, accounting for 64% of bacteriologic failures in one study. 4
Microbiologic Considerations
High-dose amoxicillin achieves 92% eradication of S. pneumoniae (including penicillin-nonsusceptible strains with MIC ≤2.0 mcg/mL) and 84% eradication of beta-lactamase-negative H. influenzae. 4
Approximately 87% of S. pneumoniae isolates are susceptible to high-dose amoxicillin versus 83% for standard-dose therapy. 1
Beta-lactamase-producing H. influenzae (present in 10-42% of cases depending on geography) and nearly 100% of M. catarrhalis are resistant to amoxicillin alone, necessitating amoxicillin-clavulanate for treatment failures. 3, 4
Pain Management
Address pain management with acetaminophen or ibuprofen regardless of antibiotic choice, as adequate analgesia is a critical component of otitis media treatment. 1, 2