What antibiotic is recommended for a bacterial sinus infection?

Recommended Antibiotics for Bacterial Sinus Infection

Amoxicillin-clavulanate is the first-line antibiotic recommended for treating bacterial sinus infections due to its effectiveness against the most common pathogens and favorable risk-benefit profile. 1

First-Line Treatment Options

Adults

• Amoxicillin with or without clavulanate is the recommended first-line therapy for most adults with acute bacterial rhinosinusitis (ABRS) 1
  • Standard dose: 500-875 mg amoxicillin twice daily for 5-10 days 1
  • High-dose amoxicillin-clavulanate (1.75-4 g/250 mg per day) may be used in areas with high prevalence of resistant pathogens or for moderate disease 1

Children

• Amoxicillin at standard dose (45 mg/kg/day) for uncomplicated cases 1
• High-dose amoxicillin (90 mg/kg/day) in communities with high prevalence of nonsusceptible S. pneumoniae (>10%) 1
• Amoxicillin-clavulanate (45-90 mg/6.4 mg per kg per day) for children under 2 years, attending daycare, or recently treated with antibiotics 1

Alternative Options for Penicillin-Allergic Patients

Non-Type I Hypersensitivity Reactions (e.g., rash)

• Second-generation cephalosporins: cefuroxime axetil 1
• Third-generation cephalosporins: cefpodoxime proxetil, cefdinir 1
• Note: Cefixime and ceftibuten have poor activity against S. pneumoniae and should not be used 1

Type I Hypersensitivity Reactions (anaphylaxis)

• Respiratory fluoroquinolones: levofloxacin, moxifloxacin (for adults only) 1
  • Should be reserved for treatment failures or complicated cases 1
• Macrolides (azithromycin, clarithromycin): less effective due to increasing resistance 1
• Clindamycin: effective against gram-positive coverage only 1
• TMP/SMX: limited effectiveness against major pathogens 1

Treatment Duration

• 5-10 days for most adults 1
• 7-14 days for children, or until symptom-free plus 7 days 1

Common Pathogens in Bacterial Sinusitis

• Streptococcus pneumoniae (including penicillin-resistant strains) 1, 2
• Haemophilus influenzae (often β-lactamase producing) 1, 2
• Moraxella catarrhalis (almost always β-lactamase producing) 1, 2
• Anaerobes and Staphylococcus aureus (more common in chronic sinusitis) 2

Special Considerations

Resistance Patterns

• 25-50% of S. pneumoniae strains are relatively or highly resistant to penicillin 1
• Nearly 50% of H. influenzae and 90-100% of M. catarrhalis are β-lactamase producing 1
• Higher doses of amoxicillin can overcome resistance in many S. pneumoniae strains 1

Treatment Failure

• If no improvement or worsening after 72 hours, consider switching to:
  • High-dose amoxicillin-clavulanate if started on amoxicillin 1
  • Respiratory fluoroquinolones (adults only) 1
  • Ceftriaxone (parenteral option) 1
  • Combination therapy in severe cases 1

Cautions

• Antibiotic treatment of uncomplicated viral upper respiratory infections is inappropriate and strongly discouraged 1
• Fluoroquinolones should be reserved for situations where major complications are likely or after failure of first-line therapy 1
• Recent studies show that high-dose vs. standard-dose amoxicillin-clavulanate may have similar efficacy but potentially more adverse effects 3, 4

Remember that antibiotics should only be prescribed when a bacterial infection is strongly suspected, as most cases of sinusitis are viral and resolve spontaneously within 7-10 days 1.