What is the recommended dose of amoxicillin (amoxicillin) for a 5-year-old child with acute otitis media (ear infection)?

Amoxicillin Dosing for Acute Otitis Media in a 5-Year-Old

For a 5-year-old child with acute otitis media, prescribe high-dose amoxicillin at 80-90 mg/kg/day divided into 2 doses daily for 10 days. 1, 2

Dose Calculation

• Calculate the child's weight in kilograms (if you have a 5-year-old weighing approximately 18-20 kg, which is typical for this age) 2, 3
• Multiply weight by 90 mg/kg/day to get the total daily dose (e.g., 20 kg × 90 mg/kg = 1800 mg/day) 2, 3
• Divide this total into 2 equal doses given every 12 hours (e.g., 900 mg twice daily) 1, 2
• Using 400 mg/5 mL suspension, this translates to approximately 11 mL twice daily for a 20 kg child 2

Why High-Dose Amoxicillin?

High-dose amoxicillin (80-90 mg/kg/day) is the evidence-based first-line treatment because it achieves middle ear fluid concentrations that overcome drug-resistant Streptococcus pneumoniae, with approximately 87% of isolates susceptible to this regimen. 1, 2

• The higher dose maintains middle ear fluid levels above the minimum inhibitory concentration for intermediately resistant S. pneumoniae (MIC 0.12-1.0 μg/mL) and many highly resistant strains (MIC ≥2 μg/mL) for longer periods during the dosing interval 1
• Standard-dose amoxicillin (40-45 mg/kg/day) is inadequate for resistant organisms, particularly when viral coinfection is present 4, 5
• High-dose amoxicillin eradicated 92% of S. pneumoniae isolates in clinical trials, including penicillin-nonsusceptible strains 5

Treatment Duration

Treat for 10 days in children under 6 years of age. 2, 3

• The American Academy of Pediatrics specifically recommends 10-day courses for younger children regardless of symptom severity 2
• Shorter courses (5 days) may be considered in children over 6 years with mild disease, but this does not apply to a 5-year-old 3

When to Switch to Amoxicillin-Clavulanate

Switch to high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate) if: 1, 2

• The child received amoxicillin in the past 30 days 1
• Concurrent purulent conjunctivitis is present 1
• No improvement or worsening occurs after 48-72 hours of amoxicillin therapy 1, 2
• History of recurrent AOM unresponsive to amoxicillin 1

The rationale for switching is that beta-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis are the predominant causes of amoxicillin treatment failure, accounting for 64% of bacteriologic failures in one study 5

Reassessment Timeline

Reassess the patient at 48-72 hours if symptoms fail to improve or worsen. 1, 2

• Clinical improvement should be evident within the first 24-48 hours 2
• If no improvement by 48-72 hours, this constitutes treatment failure requiring a change in antibiotic therapy 1, 2

Pain Management

Address pain management concurrently during the first 24 hours with acetaminophen or ibuprofen as needed. 2

• Pain control is a separate priority from antibiotic therapy and should not be overlooked 2

Critical Pitfalls to Avoid

• Never exceed 4000 mg/day total dose, even in larger or older children 2
• Do not use standard-dose amoxicillin (40-45 mg/kg/day) for acute otitis media, as it fails to achieve adequate middle ear concentrations against resistant organisms 4, 5
• Persistent middle ear effusion after treatment completion does not require additional antibiotics unless acute symptoms recur 2
• Verify the suspension concentration (200 mg/5 mL vs. 400 mg/5 mL) before calculating the volume to dispense to avoid dosing errors 2

Special Considerations

For children with penicillin allergy, alternative antibiotics include cefdinir (14 mg/kg/day) or cefuroxime (30 mg/kg/day), though these are less effective than amoxicillin for susceptible organisms 1