When to use amoxicillin (amoxicillin) in respiratory symptoms?

When to Use Amoxicillin in Respiratory Symptoms

Amoxicillin should only be used for respiratory symptoms when there is strong clinical evidence of bacterial infection, not for viral respiratory infections or mild symptoms without specific diagnostic criteria.

Upper Respiratory Tract Infections

Acute Otitis Media

• First-line treatment: Amoxicillin 80-100 mg/kg/day in three divided doses for children under 30kg; 500mg three times daily or 875mg twice daily for adults 1
• Duration: 7-10 days for adults, 10-14 days for children 2
• Consider observation first in:
  • Children >2 years with non-severe symptoms 3
  • Children 6 months to 2 years for up to 2 days before starting antibiotics 3

Acute Bacterial Sinusitis

• Indications for immediate treatment:
  • Severe purulent maxillary sinusitis 3
  • Symptoms persisting >10 days without improvement 2
  • Severe symptoms or high fever 2
  • Worsening symptoms after initial improvement 2
• First-line treatment: Amoxicillin (same dosing as above)
• Second-line treatment: Amoxicillin-clavulanate if treatment failure or high-risk factors 2

Lower Respiratory Tract Infections

Exacerbation of Simple Chronic Bronchitis

• Do not prescribe antibiotics immediately, even with fever 3
• Only prescribe if fever >38°C persists for more than 3 days 3

Exacerbation of Chronic Obstructive Bronchitis

• Immediate antibiotic therapy indicated when:
  • Patient has chronic respiratory insufficiency (dyspnea at rest and/or FEV1 <35% and hypoxemia) 3
  • At least 2 of 3 Anthonisen criteria are present:
    1. Increased dyspnea
    2. Increased sputum purulence
    3. Increased sputum volume 3, 2

Uncomplicated Lower Respiratory Tract Infections in Children

• Amoxicillin is unlikely to be clinically effective for uncomplicated chest infections in children 4
• Provide safety-netting advice instead unless pneumonia is suspected 4

Antibiotic Selection and Dosing

First-line Treatment

• Amoxicillin remains the reference compound for most respiratory infections 3
• Dosing options:
  • Adults: 1.5-4g/day (typically 500mg three times daily or 875mg twice daily) 2, 5
  • Children: 80-100mg/kg/day in three daily doses 2, 1
  • Twice daily dosing (1000mg twice daily) is as effective as three times daily dosing for bronchitis 6, 5

Second-line Treatment (when first-line fails or high-risk situations)

• Amoxicillin-clavulanate for:
  • Treatment failures 2
  • Recent antibiotic exposure (<6 weeks) 3, 2
  • Areas with high prevalence of β-lactamase-producing H. influenzae 3, 7
  • Severe symptoms 3, 2

Special Considerations

Antibiotic Resistance

• Local resistance patterns should guide therapy 3
• Avoid macrolides due to high pneumococcal resistance rates (>40%) 2
• Avoid third-generation cephalosporins as monotherapy due to pneumococcal resistance 2

Penicillin Allergy

• Alternative options:
  • Doxycycline (100mg twice daily for 5-7 days) 2
  • Respiratory fluoroquinolones (levofloxacin or moxifloxacin) - reserve for when no other options exist 2
  • Clindamycin plus a third-generation oral cephalosporin 2

Common Pitfalls to Avoid

1. Prescribing antibiotics for viral infections - most upper respiratory infections are viral and self-limiting 3
2. Not considering "wait and see" approach - observation with close follow-up is appropriate for many cases 3
3. Using inappropriate duration - shorter courses (5-7 days) are generally as effective as longer courses with fewer adverse events 2
4. Not recognizing treatment failure - clinical improvement should be evident within 48-72 hours; if not, consider alternative diagnosis or therapy 2
5. Using amoxicillin when amoxicillin-clavulanate is indicated - in areas with high β-lactamase-producing organisms, amoxicillin alone may be insufficient 7

Remember that judicious antibiotic use is essential to minimize resistance development. Clinical assessment, appropriate diagnosis, and consideration of local resistance patterns should guide the decision to use amoxicillin for respiratory symptoms.