What are the recommended antibiotics for bacterial sinus infections?

Recommended Antibiotics for Bacterial Sinus Infections

Amoxicillin remains the first-line antibiotic treatment for uncomplicated acute bacterial sinusitis in patients without risk factors for antimicrobial resistance. For patients with risk factors or more severe disease, high-dose amoxicillin-clavulanate is recommended 1.

First-Line Treatment Options

Uncomplicated Acute Bacterial Sinusitis (Mild Disease)

• Standard-dose amoxicillin: 45 mg/kg/day in 2 divided doses for children; 500 mg twice daily for adults 1
• Duration: 10-14 days (or 7 days after symptoms resolve) 1

Risk Factors for Resistant Pathogens

Risk factors that warrant broader coverage include:

• Age <2 years
• Daycare attendance
• Antimicrobial use within previous 4-6 weeks
• Moderate to severe illness
• Areas with high prevalence (>10%) of resistant S. pneumoniae 1

For Patients with Risk Factors or Moderate Disease

• High-dose amoxicillin-clavulanate:
  • Children: 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses 1
  • Adults: 875 mg amoxicillin/125 mg clavulanate twice daily 1

Alternative Options for Penicillin-Allergic Patients

Non-Type 1 Allergy

• Cephalosporins:
  • Cefdinir
  • Cefuroxime
  • Cefpodoxime 1

Type 1 (Severe) Allergy

• Respiratory fluoroquinolones (adults only):
  • Levofloxacin 500 mg daily for 10-14 days 1, 2
• Clindamycin plus a second agent for gram-negative coverage 1

Special Situations

Unable to Tolerate Oral Medication

• Ceftriaxone: 50 mg/kg (single dose) IM or IV for children who are vomiting or unable to tolerate oral medication 1

Treatment Failure

If no improvement after 72 hours of initial therapy:

1. For patients on amoxicillin: Switch to high-dose amoxicillin-clavulanate 1
2. For patients on standard therapy with risk factors: Consider respiratory fluoroquinolones (adults) or consultation 1

Pathogens and Resistance Considerations

The major bacterial pathogens in acute bacterial sinusitis are:

• Streptococcus pneumoniae (30%)
• Haemophilus influenzae (30%)
• Moraxella catarrhalis (10%) 1

Resistance patterns to consider:

• 10-15% of S. pneumoniae are resistant to penicillin nationally (up to 50-60% in some regions)
• 10-42% of H. influenzae produce β-lactamase
• Nearly 100% of M. catarrhalis produce β-lactamase 1

Important Caveats

• Avoid trimethoprim-sulfamethoxazole and macrolides (including azithromycin) due to high rates of resistance 1, 3
• Recent research suggests no benefit of high-dose over standard-dose amoxicillin-clavulanate in adults, but guidelines still recommend high-dose for patients with risk factors 4
• Staphylococcus aureus is rarely a cause of uncomplicated acute sinusitis but is significant in complications 1
• Antibiotics should only be prescribed for bacterial sinusitis, not viral upper respiratory infections 1

Duration of Therapy

While traditional courses are 10-14 days, emerging evidence supports shorter 5-day courses for uncomplicated acute maxillary sinusitis in adults with certain antibiotics like respiratory fluoroquinolones 5.

By following these evidence-based recommendations and considering local resistance patterns, clinicians can optimize treatment outcomes while minimizing antibiotic resistance development.