When should antibiotics be prescribed for an upper respiratory infection (URI) suspected to be of bacterial origin?

When to Prescribe Antibiotics for Upper Respiratory Infections

Antibiotics should only be prescribed for URIs when there is strong evidence of bacterial infection, as most URIs are viral in nature and do not require antibiotic treatment. 1

Bacterial vs. Viral URIs

When NOT to Prescribe Antibiotics

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

When to Consider Antibiotics

Acute Bacterial Sinusitis

Antibiotics may be indicated when patients present with:

• Symptoms persisting >10 days without improvement
• Severe symptoms with purulent nasal discharge and high fever (≥39°C)
• Worsening symptoms after initial improvement ("double worsening") 3, 1

Streptococcal Pharyngitis

• Only after confirmation with appropriate testing (rapid strep test or throat culture)
• Group A beta-hemolytic streptococcus (GABS) accounts for approximately 15% of pharyngitis cases 1, 4

Acute Otitis Media

• Requires middle ear effusion AND signs of inflammation:
  • Moderate or severe bulging of tympanic membrane
  • Otorrhea not due to otitis externa
  • Mild bulging of tympanic membrane with ear pain or erythema 3

Antibiotic Selection

First-Line Agents

• Acute Bacterial Sinusitis: Amoxicillin (standard dose) or amoxicillin-clavulanate for severe cases 1, 5
• Streptococcal Pharyngitis: Penicillin for 10-14 days to prevent complications such as acute rheumatic fever 4
• Acute Otitis Media: Amoxicillin at appropriate weight-based dosing 5

Alternative Agents (for penicillin allergy)

• Cefpodoxime-proxetil or cefuroxime-axetil for non-anaphylactic penicillin allergy
• Macrolides for patients with severe penicillin allergy 1

Dosing Considerations

For adults with URI infections:

• Amoxicillin: 500 mg every 12 hours (mild/moderate) or 875 mg every 12 hours (severe)
• Treatment duration: 7-10 days for most infections, with at least 10 days for streptococcal infections 5

For pediatric patients:

• Weight-based dosing: 25-45 mg/kg/day divided every 12 hours depending on severity
• Treatment should continue for at least 48-72 hours beyond symptom resolution 5

Antibiotic Stewardship Considerations

• Inappropriate antibiotic use contributes to antibiotic resistance and unnecessary adverse events 3
• As many as 10 million antibiotic prescriptions per year are directed toward respiratory conditions for which they are unlikely to provide benefit 3
• Broad-spectrum antibiotics should not be used when narrower-spectrum alternatives would be appropriate 1

Monitoring and Follow-up

• Monitor for clinical improvement within 48-72 hours of starting therapy
• Reassess if symptoms worsen or fail to improve after 72 hours
• Educate patients on expected duration of symptoms (typically 7-10 days) and when to seek further care 1

Common Pitfalls to Avoid

1. Prescribing antibiotics for viral URIs due to patient pressure
2. Using broad-spectrum antibiotics when narrow-spectrum would suffice
3. Inadequate duration of therapy for streptococcal infections (should be at least 10 days)
4. Failing to apply stringent diagnostic criteria before diagnosing bacterial infections
5. Not considering local resistance patterns when selecting antibiotics

By following these evidence-based guidelines, clinicians can ensure appropriate antibiotic use for URIs, improving patient outcomes while minimizing antibiotic resistance.