What is the recommended antibiotic, dose, and treatment duration for bacterial sinus infections?

Antibiotic Treatment for Bacterial Sinus Infections

For adults with acute bacterial rhinosinusitis (ABRS), amoxicillin-clavulanate is the recommended first-line antibiotic at a dose of 875/125 mg twice daily for 5-10 days, with shorter courses (5-7 days) preferred for uncomplicated cases to minimize adverse effects. 1

First-Line Antibiotic Selection

Standard Cases:

• First choice: Amoxicillin-clavulanate 875/125 mg twice daily 1
• Alternative: Amoxicillin alone (1.5-4 g/day) for uncomplicated cases in areas with low resistance rates 1

High-Risk Cases:

High-dose amoxicillin-clavulanate (2 g/125 mg twice daily) is recommended for patients with:

• Geographic regions with high endemic rates (>10%) of penicillin-nonsusceptible S. pneumoniae
• Severe infection (temperature ≥39°C/102°F)
• Age >65 years
• Recent hospitalization
• Antibiotic use within the past month
• Immunocompromised status 1

Penicillin-Allergic Patients:

• Non-type I hypersensitivity: Cefpodoxime proxetil, cefuroxime axetil, or cefdinir 1
• Type I hypersensitivity: Doxycycline or respiratory fluoroquinolones (levofloxacin or moxifloxacin) 1
• Alternative combination: Clindamycin plus a third-generation oral cephalosporin (cefixime or cefpodoxime) 1

Duration of Therapy

• Standard duration: 5-10 days 1
• Shorter courses (5-7 days) are preferred when possible, as they have similar efficacy to 10-day courses with fewer adverse effects 1, 2
• Consider longer treatment (10 days) for:
  • Severe infections
  • Immunocompromised patients
  • Complications or slow response 1

Common Pathogens

The most common bacterial pathogens in ABRS are:

• Streptococcus pneumoniae
• Haemophilus influenzae
• Moraxella catarrhalis 1

Clinical Pearls and Pitfalls

• Avoid macrolides (azithromycin, clarithromycin) and trimethoprim-sulfamethoxazole as first-line therapy due to high resistance rates (>40% for macrolides against S. pneumoniae) 1
• Monitor for treatment failure: If no improvement after 7 days or worsening at any time, reassess diagnosis and consider changing antibiotics 1
• Adverse events occur in 15-40% of patients on antibiotics, most commonly gastrointestinal issues (nausea, diarrhea) 1
• Watchful waiting is an appropriate initial strategy for uncomplicated cases, with antibiotics started if no improvement after 7 days or worsening at any time 1
• High-dose immediate-release amoxicillin formulations may provide more rapid improvement than standard doses, but also increase risk of severe diarrhea 3, 4

Special Populations

Children:

• First choice: Amoxicillin-clavulanate (80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day of clavulanate in 2 divided doses) 1
• Alternative: High-dose amoxicillin (90 mg/kg/day) for areas with high pneumococcal resistance 1

Frontal, Ethmoidal, or Sphenoidal Sinusitis:

These require more aggressive treatment than maxillary sinusitis, with definite indication for antibiotic therapy. Consider fluoroquinolones active against pneumococci (levofloxacin, moxifloxacin) for these cases 1

Remember that bacterial sinusitis should be distinguished from viral rhinosinusitis, which does not require antibiotics. Bacterial sinusitis is typically diagnosed when symptoms persist beyond 10 days without improvement, worsen after initial improvement, or are severe from the onset with high fever and purulent discharge for 3-4 consecutive days 1.