What is the recommended dose and duration of antibiotics for bacterial sinusitis?

Recommended Dose and Duration of Antibiotics for Bacterial Sinusitis

For bacterial sinusitis, amoxicillin-clavulanate is the first-line antibiotic treatment with a recommended duration of 5-7 days for adults and 10-14 days for children. 1

First-Line Antibiotic Selection

Adults:

• First choice: Amoxicillin-clavulanate 1
  • Standard dose: 875 mg amoxicillin/125 mg clavulanate twice daily
  • High-dose: 2000 mg amoxicillin/125 mg clavulanate twice daily (not to exceed 2 g per dose)

Children:

• First choice: Amoxicillin-clavulanate 1
  • Standard dose: 45 mg/kg/day in 2 divided doses
  • High-dose: 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day of clavulanate in 2 divided doses (not to exceed 2 g per dose)

When to Use High-Dose Formulation

• Patients with risk factors for resistant organisms:
  • Age <2 years (children)
  • Daycare attendance
  • Recent antibiotic use (within past 4-6 weeks)
  • Areas with high prevalence (>10%) of penicillin-resistant S. pneumoniae
  • Moderate to severe illness
  • Immunocompromised state 1

Duration of Treatment

Adults:

• 5-7 days for uncomplicated acute bacterial sinusitis 1
• Some guidelines still recommend 7-10 days 1
• Newer antibiotics (fluoroquinolones) may be effective with shorter courses (5 days) 2, 3

Children:

• 10-14 days is still recommended 1

Alternative Antibiotics (for penicillin allergy or treatment failure)

Adults:

• Respiratory fluoroquinolones (levofloxacin 500 mg daily for 10-14 days or 750 mg daily for 5 days; moxifloxacin 400 mg daily for 5-10 days) 1, 2, 4
• Cephalosporins (if no immediate hypersensitivity to penicillin):
  • Cefuroxime axetil (500 mg twice daily)
  • Cefpodoxime proxetil
  • Cefdinir 1
• Macrolides (in areas with low S. pneumoniae resistance) 1
• Doxycycline (for non-pregnant adults) 1

Children:

• Cephalosporins (if no immediate hypersensitivity to penicillin) 1
• A single 50 mg/kg dose of ceftriaxone (IV/IM) can be used for children unable to tolerate oral medication initially 1

Treatment Failure Protocol

If symptoms worsen after 48-72 hours or fail to improve after 3-5 days of initial therapy:

1. Switch to high-dose amoxicillin-clavulanate if started on standard dose
2. Switch to a different antibiotic class (fluoroquinolone in adults or appropriate alternative in children)
3. Consider sinus imaging
4. Consider referral to specialist if multiple treatment failures 1

Adjunctive Therapies

• Recommended:

  • Intranasal saline irrigation (physiologic or hypertonic) 1
  • Intranasal corticosteroids, especially in patients with history of allergic rhinitis 1
  • Analgesics (acetaminophen or ibuprofen) for pain and fever 1

• Not recommended:

  • Antihistamines (unless concurrent allergic rhinitis) 1
  • Oral or topical decongestants 1

Important Clinical Pearls

• Bacterial sinusitis is uncommon in patients with symptoms lasting less than 10 days; consider delaying antibiotics in early presentations 1
• Patients should be instructed to call if symptoms worsen (especially with headache or high fever) or if symptoms haven't improved within 3-5 days of treatment 1
• For partial response at the end of initial treatment, continue antibiotic therapy for another 7-10 days 1
• Sinusitis that fails to improve after 21-28 days of initial treatment may require broader-spectrum antibiotics and consideration of anaerobic coverage 1
• Recent research shows no significant benefit of high-dose over standard-dose amoxicillin-clavulanate for adults, but increased risk of diarrhea with high-dose formulations 5, 6

By following these evidence-based recommendations for antibiotic selection and duration, clinicians can optimize treatment outcomes while minimizing adverse effects and antibiotic resistance.