What is the recommended dose of amoxicillin (amoxicillin) for acute bacterial upper respiratory infection?

Amoxicillin Dosing for Acute Bacterial Upper Respiratory Infections

For acute bacterial upper respiratory infections, amoxicillin should be dosed at 1.5-4g/day (typically 500mg three times daily or 875mg twice daily) for adults, and 80-100mg/kg/day divided into three doses for children under 30kg. 1, 2

Adult Dosing

First-line therapy (no recent antibiotic use):

• Standard dose: 1.5g/day (500mg three times daily) 1
• High dose: 4g/day (recommended when penicillin-resistant S. pneumoniae is suspected) 1
• Duration: 5-7 days for adults 1

Alternative regimen:

• 875mg twice daily (equivalent efficacy to 500mg three times daily with improved compliance) 3

Pediatric Dosing

• Children under 30kg: 80-100mg/kg/day divided into three daily doses 1, 2
• Children over 30kg: Adult dosing applies
• Duration: 10-14 days (longer course still recommended for children) 1

Clinical Considerations

When to use high-dose amoxicillin:

• Suspected penicillin-resistant S. pneumoniae
• Areas with high prevalence of drug-resistant pathogens
• Patients with severe symptoms or at high risk of complications
• Recent antibiotic exposure within 4-6 weeks 1

When to consider amoxicillin-clavulanate instead:

• When beta-lactamase producing organisms are suspected
• Treatment failure with amoxicillin alone
• Patients with comorbidities or immunocompromised status
• Recent antibiotic use within 4-6 weeks 1, 4

Monitoring and Follow-up

• Assess clinical response after 48-72 hours 1, 2
• If symptoms worsen or fail to improve after 72 hours, consider:
  1. Alternative diagnosis
  2. Switch to amoxicillin-clavulanate
  3. Add coverage for atypical pathogens
  4. Consider referral or imaging studies 1

Important Caveats

• Amoxicillin should be taken at the start of a meal to minimize gastrointestinal intolerance 5
• Complete the full course of antibiotics even if symptoms improve quickly 2
• For patients with severe renal impairment (GFR <30 mL/min), dose adjustment is required 5
• Patients with penicillin allergy should receive alternative therapy such as macrolides or doxycycline, though these have higher failure rates (20-25%) 1

Special Populations

• Elderly: Standard adult dosing, but consider renal function
• Pregnancy: Amoxicillin is generally considered safe; standard dosing applies
• Renal impairment: For GFR 10-30 mL/min: 250-500mg every 12 hours; For GFR <10 mL/min: 250-500mg every 24 hours 5

Amoxicillin remains the first-line antibiotic for most acute bacterial upper respiratory infections due to its excellent activity against Streptococcus pneumoniae, the most common bacterial pathogen in these infections.