What is the recommended treatment for upper respiratory infections with amoxicillin?

Amoxicillin for Upper Respiratory Tract Infections

Amoxicillin should only be prescribed for upper respiratory tract infections (URTIs) when there is strong evidence of bacterial infection, as most URTIs are viral in nature and do not require antibiotic therapy. 1, 2

Appropriate Indications for Amoxicillin in URTIs

Bacterial Pharyngitis

• Amoxicillin is indicated for Group A β-hemolytic streptococcal (GABHS) pharyngitis
• GABHS causes ~10% of adult cases and 15-30% of cases in children 1
• Diagnosis should be confirmed by:
  • Clinical criteria (Centor criteria) 3
  • Rapid antigen test or throat culture 3
• Dosing: Penicillin V is actually the treatment of choice for streptococcal pharyngitis 3
  • If amoxicillin is used: 500 mg every 12 hours (adults) or 25-45 mg/kg/day divided every 12 hours (children) for 10 days 1, 4

Acute Otitis Media (AOM)

• Amoxicillin is the drug of choice given low penicillin resistance rates for S. pneumoniae in many regions 3
• Indicated for:
  • All children <2 years of age
  • Children >2 years with bilateral AOM, otorrhea, co-morbidities, or severe illness 3
• Dosing:
  • Standard dose: 35-45 mg/kg/day 5
  • High-dose: 80-90 mg/kg/day for high-risk NSSP (non-susceptible S. pneumoniae) areas 5

Acute Bacterial Sinusitis

• Indicated when symptoms:
  • Persist >10 days without improvement
  • Are severe with purulent discharge and high fever (≥39°C)
  • Worsen after initial improvement ("double worsening") 1
• Amoxicillin is the drug of choice 3
• Duration: 7-10 days 1

When NOT to Use Amoxicillin

Antibiotics should not be prescribed for:

• Common cold
• Viral rhinosinusitis
• Acute bronchitis (in most cases)
• Laryngitis
• COVID-19
• Influenza 1, 2

Bacterial Susceptibility Considerations

• Amoxicillin is only effective against β-lactamase–negative isolates of:

  • Streptococcus species (α-and β-hemolytic isolates)
  • Streptococcus pneumoniae
  • Staphylococcus spp.
  • Haemophilus influenzae 4

• For β-lactamase-producing pathogens, consider amoxicillin-clavulanate instead 3, 6

Treatment Algorithm

1. Assess likelihood of bacterial infection:

   • Duration >10 days without improvement
   • Severe symptoms with purulent discharge and high fever
   • Worsening after initial improvement 1

2. Select appropriate antibiotic based on suspected pathogen:

   • For suspected streptococcal pharyngitis: Amoxicillin
   • For AOM: Standard-dose amoxicillin (first-line)
   • For sinusitis: Amoxicillin (first-line)
   • For patients with risk factors for resistant organisms: Amoxicillin-clavulanate 1, 3

3. Determine appropriate dosing:

   • Adults: 500 mg every 12 hours (mild/moderate) or 875 mg every 12 hours (severe) 1
   • Children: 25-45 mg/kg/day divided every 12 hours (standard dose) or 80-90 mg/kg/day (high-dose for suspected resistant organisms) 1, 5

4. Set appropriate duration:

   • 7-10 days for most infections
   • At least 10 days for streptococcal infections 1
   • Continue for 48-72 hours beyond symptom resolution 4

5. Monitor response:

   • Assess for clinical improvement within 48-72 hours
   • If no improvement after 48 hours, consider atypical bacteria and macrolide therapy 7
   • If worsening or no improvement after 72 hours, reassess diagnosis 1

Important Caveats

• Take amoxicillin at the start of a meal to minimize gastrointestinal intolerance 4
• Inappropriate antibiotic use contributes to antibiotic resistance and adverse events 1, 2
• Local resistance patterns should guide therapy - community-specific recommendations may be appropriate 5
• In children >3 years with suspected atypical bacteria (Mycoplasma pneumoniae, Chlamydia pneumoniae), macrolides may be more appropriate than amoxicillin 7, 1