What is a suitable antibiotic for a patient with sinusitis and no allergies?

First-Line Antibiotic Treatment for Sinusitis

Amoxicillin-clavulanate (875/125 mg twice daily for 5-7 days) is the recommended first-line treatment for sinusitis in patients with no allergies, providing excellent coverage against common pathogens including Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis. 1

Antibiotic Selection Algorithm

1. First-line therapy:

   • Amoxicillin-clavulanate 875/125 mg twice daily for 5-7 days
   • Provides broad coverage against the most common pathogens including beta-lactamase producing organisms

2. For patients with low risk of resistant pathogens:

   • Standard-dose amoxicillin-clavulanate is sufficient
   • Recent evidence shows no additional benefit of high-dose compared to standard-dose amoxicillin-clavulanate 2

3. For patients with high risk of resistant pathogens:

   • High-dose amoxicillin-clavulanate (2000 mg amoxicillin component twice daily)
   • Risk factors include: recent antibiotic use, healthcare exposure, or areas with high prevalence of resistant S. pneumoniae

4. Alternative options (if first-line cannot be used):

   • Cefuroxime 500 mg twice daily for 5-7 days
   • Cefpodoxime 200-400 mg twice daily for 5-7 days
   • Cefdinir 14 mg/kg/day divided once or twice daily for 5-7 days 1

5. For fluoroquinolone consideration:

   • Levofloxacin 750 mg once daily for 5 days or 500 mg once daily for 10 days
   • Shown to be effective for acute bacterial sinusitis 3
   • Should be reserved for treatment failures or patients with allergies to first-line agents due to risk of adverse effects and antimicrobial stewardship concerns

Clinical Considerations

Duration of Therapy

• Current evidence supports shorter courses (5-7 days) of antibiotic therapy for uncomplicated acute sinusitis 1
• Treatment should be continued until 7 days after symptom resolution in more severe cases

Treatment Failure

• If no improvement after 72 hours of initial therapy, reassess diagnosis and consider switching antibiotics 1
• Inadequate duration of therapy can lead to relapse, reported in 7.7% of cases 1

Common Pathogens in Sinusitis

• Streptococcus pneumoniae
• Haemophilus influenzae
• Moraxella catarrhalis 4, 1

Important Caveats

• Antibiotic treatment is inappropriate for uncomplicated viral upper respiratory tract infections 4

• Diagnosis of bacterial sinusitis should be based on clinical presentation including:

  1. Persistent symptoms (>10 days without improvement)
  2. Severe symptoms (high fever and purulent nasal discharge for 3-4 consecutive days)
  3. Worsening symptoms after initial improvement 5

• Adverse effects: Diarrhea is common with amoxicillin-clavulanate (reported in approximately 40% of patients) 2

• Levofloxacin has fewer gastrointestinal side effects compared to amoxicillin-clavulanate (7.4% vs 21.2%) but should be reserved for specific cases due to other potential adverse effects 6

• Adjunctive therapies such as intranasal corticosteroids, intranasal saline irrigation, and analgesics may provide symptom relief alongside antibiotic therapy 1