What is the recommended dose of amoxicillin (Amox) in mL for a 5-year-old patient weighing 25 kg with otitis media, using the 400/5 suspension?

Amoxicillin Dosing for 5-Year-Old with Otitis Media (25 kg, 400/5 Suspension)

Administer 14 mL of the 400/5 suspension twice daily (every 12 hours) for 10 days, providing 2240 mg/day total (approximately 90 mg/kg/day).

Dose Calculation

• The American Academy of Pediatrics recommends high-dose amoxicillin at 80-90 mg/kg/day divided into 2 doses as first-line therapy for acute otitis media 1, 2, 3
• For a 25 kg child: 90 mg/kg/day × 25 kg = 2250 mg/day total 1
• Divided into 2 doses: 1125 mg per dose 1
• Using 400/5 suspension (80 mg/mL): 1125 mg ÷ 80 mg/mL = 14.06 mL per dose 1
• Practical dosing: 14 mL twice daily = 1120 mg per dose = 2240 mg/day (89.6 mg/kg/day) 1

Rationale for High-Dose Therapy

• High-dose amoxicillin (80-90 mg/kg/day) achieves adequate middle ear fluid concentrations to cover drug-resistant Streptococcus pneumoniae, the primary concern in otitis media 1, 3, 4
• Approximately 87% of S. pneumoniae isolates are susceptible to high-dose amoxicillin versus only 83% for standard-dose therapy 1, 3
• High-dose therapy maintains middle ear fluid levels above the minimum inhibitory concentration for intermediately resistant S. pneumoniae for longer durations 3, 5

Treatment Duration

• Treat for 10 days in children under 6 years of age 1, 2
• The American Academy of Pediatrics specifically recommends 10-day courses for younger children with any severity of symptoms 1

Reassessment and Treatment Failure

• Reassess at 48-72 hours if symptoms fail to improve or worsen 1, 2, 3
• If no improvement by 48-72 hours, switch to high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate) 1, 2, 3
• Beta-lactamase-producing Haemophilus influenzae is the predominant pathogen in amoxicillin treatment failures, accounting for 64% of bacteriologic failures 4

Pain Management

• Address pain management concurrently during the first 24 hours regardless of antibiotic choice 1, 2, 3
• Use acetaminophen or ibuprofen as needed 6

Common Pitfalls to Avoid

• Do not use standard-dose amoxicillin (40-45 mg/kg/day) for empiric treatment in areas with drug-resistant S. pneumoniae 5, 4, 7
• Do not exceed 4000 mg/day total dose, even in larger children 1
• Persistent middle ear effusion after treatment (present in 60-70% at 2 weeks, 40% at 1 month) does not require additional antibiotics unless acute symptoms recur 1