What are the recommended antibiotics for acute bacterial sinusitis according to Queensland guidelines?

Queensland Guidelines for Antibiotics in Acute Bacterial Sinusitis

According to the most recent guidelines, high-dose amoxicillin-clavulanate (875/125 mg twice daily for adults) is the recommended first-line antibiotic treatment for acute bacterial sinusitis in Queensland. 1

First-Line Treatment Options

Adults:

• First choice: Amoxicillin-clavulanate 875/125 mg twice daily for 5-7 days 1
• High-dose option: 2000 mg amoxicillin component twice daily for 5-7 days (for severe cases or high-risk patients) 1

Children:

• First choice: Amoxicillin 45 mg/kg/day in 2 divided doses 2
• High-dose option: Amoxicillin-clavulanate (80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day of clavulanate) in 2 divided doses for:
  • Children younger than 2 years
  • Those attending childcare
  • Recent antibiotic use (within 4 weeks)
  • Moderate to severe illness 2

Alternative Options for Penicillin-Allergic Patients

For patients with penicillin allergy, the following alternatives are recommended:

• Cefdinir 300 mg twice daily
• Cefpodoxime 200 mg twice daily
• Cefuroxime axetil 500 mg twice daily 1

Pathogens and Resistance Considerations

The main bacterial pathogens in acute bacterial sinusitis are:

• Streptococcus pneumoniae
• Haemophilus influenzae
• Moraxella catarrhalis 2, 1

Antimicrobial resistance patterns vary by region, with:

• 10-15% of S. pneumoniae isolates showing nonsusceptibility to penicillin nationally (up to 50-60% in some areas)
• 10-42% of H. influenzae and nearly 100% of M. catarrhalis producing β-lactamase 2

Treatment Duration

The recommended duration of treatment is 5-7 days 1. This shorter course is supported by evidence showing comparable efficacy to traditional 10-14 day regimens while potentially reducing antibiotic resistance and side effects.

Treatment Failure Protocol

If no improvement is observed after 72 hours of treatment:

1. Reassess the diagnosis
2. Consider switching to an alternative antibiotic
3. Consider referral to a specialist if symptoms are worsening 1

Special Considerations

• Risk factors for resistant organisms: Recent antibiotic use (within 30 days), age younger than 2 years, and childcare attendance 2
• Severe cases: For patients unable to tolerate oral medication or with severe symptoms, a single 50 mg/kg dose of ceftriaxone (IV or IM) can be used initially 2
• Post-treatment follow-up: Patients should be reassessed within 3-5 days of starting treatment to evaluate effectiveness 1

Common Pitfalls to Avoid

1. Overdiagnosis: Distinguishing viral from bacterial sinusitis is crucial. Bacterial sinusitis should be suspected with:

   • Persistent symptoms >10 days without improvement
   • Severe symptoms with high fever and purulent discharge for 3-4 consecutive days
   • Worsening symptoms after initial improvement

2. Inappropriate antibiotic selection: Using macrolides (clarithromycin, azithromycin) as first-line therapy is not recommended due to high rates of resistance among S. pneumoniae.

3. Inadequate dosing: Standard-dose amoxicillin may be insufficient in areas with high prevalence of resistant S. pneumoniae.

4. Premature treatment changes: Allow 72 hours for clinical response before considering a change in therapy.