What antibiotics are recommended for the treatment of bacterial sinusitis?

Antibiotic Treatment for Bacterial Sinusitis

For bacterial sinusitis, amoxicillin is the recommended first-line antibiotic treatment, with amoxicillin-clavulanate as the preferred option for more severe infections or when there are risk factors for resistant pathogens. 1

First-Line Antibiotic Options

Adults:

• Standard-dose amoxicillin: 500 mg twice daily 2, 1
• High-dose amoxicillin: 875 mg twice daily (for areas with high prevalence of resistant S. pneumoniae) 1
• Amoxicillin-clavulanate: 500-875 mg (amoxicillin component) twice daily 2, 1

Children:

• Standard-dose amoxicillin: 45 mg/kg/day in 2 divided doses 1
• High-dose amoxicillin: 80-90 mg/kg/day in 2 divided doses (for areas with high prevalence of resistant S. pneumoniae) 1
• Amoxicillin-clavulanate: 45 mg/6.4 mg per kg per day (standard) or 90 mg/6.4 mg per kg per day (high-dose) 2

Alternative Options for Penicillin-Allergic Patients

• Cephalosporins (if no history of anaphylaxis to penicillin): 1

  • Cefuroxime axetil: 250-500 mg twice daily 2
  • Cefpodoxime proxetil: 200-400 mg twice daily 2
  • Cefdinir: dosage varies by age/weight 2
  • Cefprozil: 250-500 mg twice daily 2

• Macrolides (for patients with severe penicillin allergy): 1

  • Azithromycin: 500 mg once daily for 3 days 3
  • Clarithromycin: 500 mg twice daily 2

• For severe infections in penicillin-allergic patients:

  • Respiratory fluoroquinolones (adults only): 2, 4
    • Levofloxacin: 500 mg once daily for 10-14 days or 750 mg once daily for 5 days 4
    • Moxifloxacin: 400 mg once daily 2

Treatment Duration

• Standard treatment duration: 10-14 days for acute bacterial sinusitis 2, 1
• Shorter courses (5-7 days) may be effective with newer agents like respiratory fluoroquinolones 4
• Treatment should continue until the patient is symptom-free for 7 days 1

Treatment Based on Severity and Risk Factors

Mild to Moderate Uncomplicated Sinusitis:

• First-line: Amoxicillin 500 mg twice daily 1
• Duration: 10-14 days 2, 1

Severe Infection or Risk Factors for Resistant Pathogens:

• Risk factors include: recent antibiotic use, age >65 years, hospitalization within past 5 days, immunocompromised state 2
• Recommended: Amoxicillin-clavulanate 875/125 mg twice daily 2, 1
• Alternative: Respiratory fluoroquinolone (adults only) 2, 4

Treatment Failure Protocol:

• If no improvement after 72 hours of initial therapy, switch to a different antibiotic class 2, 1
• Consider high-dose amoxicillin-clavulanate if started on amoxicillin alone 1, 5
• Consider respiratory fluoroquinolone if not previously used 4, 6

Common Pathogens in Bacterial Sinusitis

• Primary pathogens: 2

  • Streptococcus pneumoniae
  • Haemophilus influenzae
  • Moraxella catarrhalis (especially in children)

• Less common pathogens: 2

  • Staphylococcus aureus
  • Anaerobes
  • Gram-negative bacteria

Important Considerations

• Antibiotics should only be prescribed for suspected bacterial sinusitis, not viral sinusitis 2, 1
• Bacterial sinusitis is typically diagnosed when symptoms persist >10 days or worsen after 5-7 days 2
• Recent antibiotic use is a major risk factor for infection with resistant pathogens 2
• High-dose amoxicillin-clavulanate may not provide significant additional benefit over standard-dose therapy but may increase side effects like diarrhea 5, 7
• Twice-daily dosing of amoxicillin-clavulanate (875/125 mg) is as effective as three-times-daily dosing (500/125 mg) 8
• Fluoroquinolones should be reserved for patients who have failed other therapies or have risk factors for resistant pathogens due to their broad spectrum and potential for developing resistance 2, 4

Adjunctive Therapies

• Intranasal corticosteroids are recommended as an adjunct to antibiotic therapy 1
• Short-term oral corticosteroids may be considered for patients with marked mucosal edema or who fail to respond to initial treatment 1
• Adequate hydration, analgesics, and nasal saline irrigation may provide symptomatic relief 1