What is the first‑line antibiotic and dosing regimen for a 5‑year‑old boy (16.78 kg) with acute otitis media and no drug allergies?

Antibiotic Management for a 5-Year-Old with Acute Otitis Media

Prescribe high-dose amoxicillin 80–90 mg/kg/day divided into two doses (approximately 670–755 mg per dose, given every 12 hours) for 7 days if symptoms are mild-to-moderate, or 10 days if severe. 1

Calculating the Exact Dose

For this 16.78 kg child:

• Total daily dose: 1,342–1,510 mg/day (80–90 mg/kg × 16.78 kg) 1
• Per-dose amount: 671–755 mg every 12 hours 1
• Practical prescription: Amoxicillin 750 mg twice daily (falls within the recommended range and uses standard suspension concentrations) 1

Treatment Duration by Severity

Mild-to-moderate symptoms (low-grade fever <39°C, mild otalgia <48 hours):

• 7-day course is equally effective as 10 days for children aged 2–5 years 1

Severe symptoms (moderate-to-severe otalgia, otalgia ≥48 hours, or fever ≥39°C):

• 10-day course is required 1

Pain Management (Mandatory First Step)

• Initiate weight-based ibuprofen or acetaminophen immediately for all children with ear pain, regardless of antibiotic decision 1
• Analgesics provide relief within 24 hours, whereas antibiotics show no symptomatic benefit in the first 24 hours 1
• Continue pain medication throughout the acute phase 1

When to Switch to Amoxicillin-Clavulanate as First-Line

Use amoxicillin-clavulanate (90 mg/kg/day amoxicillin component + 6.4 mg/kg/day clavulanate, divided twice daily) instead of plain amoxicillin when any of these factors are present: 1

• Amoxicillin use within the previous 30 days 1
• Concurrent purulent conjunctivitis (suggests Haemophilus influenzae) 1
• Daycare attendance or high local prevalence of β-lactamase-producing organisms 1

For this 16.78 kg child, that would be approximately 1,510 mg amoxicillin component daily (755 mg twice daily). 1

Reassessment Protocol

Re-evaluate at 48–72 hours if: 1

• Symptoms worsen at any time 1
• No improvement occurs within 48–72 hours 1
• Persistent high fever or worsening ear pain develops 1

Treatment Failure Algorithm

1. If plain amoxicillin fails: Switch to high-dose amoxicillin-clavulanate (90 mg/kg/day amoxicillin component) 1

2. If amoxicillin-clavulanate fails: Administer intramuscular ceftriaxone 50 mg/kg once daily for 3 consecutive days (a 3-day course is superior to single-dose) 1

3. After multiple failures: Consider tympanocentesis with culture and susceptibility testing 1

Penicillin Allergy Alternatives

For non-severe penicillin allergy (non-IgE-mediated), use oral cephalosporins with negligible cross-reactivity (<0.1%): 1

• Cefdinir 14 mg/kg/day once daily (preferred for convenience) = approximately 235 mg once daily 1
• Cefuroxime 30 mg/kg/day divided twice daily = approximately 250 mg twice daily 1
• Cefpodoxime 10 mg/kg/day divided twice daily = approximately 84 mg twice daily 1

Critical Pitfalls to Avoid

• Do not use shorter courses (<7 days) in children under 6 years with mild-moderate disease; the evidence supports 7 days minimum for this age group 1
• Never prescribe trimethoprim-sulfamethoxazole or erythromycin-sulfisoxazole for treatment failures—pneumococcal resistance to these agents is substantial 1
• Do not prescribe azithromycin as first-line therapy—macrolide resistance exceeds 40% in the United States, with bacterial failure rates of 20–25% 1
• Avoid treating isolated tympanic membrane redness without documented middle ear effusion—this does not constitute AOM 1

Expected Post-Treatment Course

• Middle ear effusion persists in 60–70% of children at 2 weeks after successful treatment, declining to 40% at 1 month and 10–25% at 3 months 1
• This persistent effusion without acute symptoms represents otitis media with effusion (OME), not treatment failure, and requires only observation—no additional antibiotics 1
• Complete the full antibiotic course even if symptoms resolve earlier, to minimize relapse 2

Observation Without Antibiotics (Alternative Strategy)

For children ≥2 years with non-severe AOM and reliable 48–72 hour follow-up, observation without immediate antibiotics is appropriate: 1

• Provide a safety-net prescription to be filled only if symptoms worsen or fail to improve within 48–72 hours 1
• Requires a mechanism to ensure follow-up (scheduled visit or telephone contact) 1
• Shared decision-making with parents is essential 1

However, immediate antibiotics are mandatory for: 1

• Children <6 months (any severity) 1
• Children 6–23 months with bilateral AOM or severe symptoms 1
• Any child when follow-up cannot be ensured 1