What are the recommended antibiotics for acute sinus infection?

Recommended Antibiotics for Acute Sinus Infection

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 7-10 days is the preferred first-line antibiotic for acute bacterial sinusitis in adults. 1, 2

When Antibiotics Are Indicated

Antibiotics should only be prescribed when acute bacterial sinusitis is confirmed by one of three clinical patterns: 1

• Persistent symptoms ≥10 days without improvement (nasal discharge, congestion, facial pain/pressure) 1
• Severe symptoms for ≥3 consecutive days (fever >39°C, purulent nasal discharge, facial pain) 1
• Double worsening - initial improvement from viral URI followed by worsening symptoms 1

Unilateral or bilateral infraorbital pain that worsens when bending forward strongly suggests bacterial sinusitis. 1

First-Line Treatment Selection

Amoxicillin-clavulanate 875 mg/125 mg twice daily is recommended over plain amoxicillin due to increasing prevalence of beta-lactamase-producing organisms (H. influenzae and M. catarrhalis). 1, 2 The Infectious Diseases Society of America and American College of Physicians both prioritize this combination as first-line therapy. 1, 2

Plain amoxicillin (500 mg twice daily for mild infections or 875 mg twice daily for moderate infections) remains acceptable only for uncomplicated cases in patients without recent antibiotic exposure. 1, 3

Treatment duration: 7-10 days until symptom-free for 7 days, typically totaling 10-14 days. 1, 2 Some cephalosporins are effective in shorter 5-day courses. 1

Penicillin-Allergic Patients

For documented penicillin allergy, use second- or third-generation cephalosporins as first-line alternatives: 1, 2, 3

• Second-generation: Cefuroxime-axetil 1, 3
• Third-generation: Cefpodoxime-proxetil, cefdinir, or cefotiam-hexetil 1, 3

The risk of cross-reactivity between penicillins and second/third-generation cephalosporins is negligible. 1

Do not use azithromycin or other macrolides - resistance rates of 20-25% make them unsuitable for acute bacterial sinusitis, even in penicillin-allergic patients. 1, 4 French guidelines and the American Academy of Pediatrics explicitly exclude macrolides due to resistance patterns. 1

Second-Line Treatment for Treatment Failure

If no improvement occurs after 3-5 days of initial therapy, switch to: 1, 2

• High-dose amoxicillin-clavulanate (if not already used) 1, 2
• Respiratory fluoroquinolones: Levofloxacin 750 mg daily for 5 days or 500 mg daily for 10 days; moxifloxacin 400 mg daily for 10 days 1, 2, 5

Fluoroquinolones provide 90-92% predicted clinical efficacy and excellent coverage against multi-drug resistant S. pneumoniae (MDRSP). 1, 5 However, fluoroquinolones should not be used as routine first-line therapy due to resistance concerns. 1

Treatment Based on Anatomic Location

Maxillary sinusitis (most common): Use standard first-line antibiotics (amoxicillin-clavulanate). 2, 3

Frontal, ethmoidal, or sphenoidal sinusitis: Consider fluoroquinolones (levofloxacin or moxifloxacin) due to higher risk of serious complications. 2, 3 These locations warrant more aggressive initial therapy.

Adjunctive Therapies

• Intranasal corticosteroids are recommended as adjuncts to antibiotic therapy for all patients with acute bacterial sinusitis 1, 2, 3
• Short-term oral corticosteroids (e.g., dexamethasone 4 mg) for acute hyperalgic sinusitis (severe pain) or marked mucosal edema 1, 2, 3
• Analgesics (acetaminophen, NSAIDs) for pain relief 1
• Saline nasal irrigation for symptomatic relief 1

Pediatric Dosing

For children with acute bacterial sinusitis: 1, 2

• Standard dose: Amoxicillin 45 mg/kg/day in 2 divided doses 1, 2
• High-dose: Amoxicillin 80-90 mg/kg/day in 2 divided doses for areas with high prevalence of resistant S. pneumoniae or risk factors (age <2 years, daycare attendance, recent antibiotic use) 1, 2
• Amoxicillin-clavulanate: 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses for children with risk factors 1

For penicillin-allergic children, use cefpodoxime proxetil 8 mg/kg/day in two doses. 1

Critical Pitfalls to Avoid

• Inadequate treatment duration leads to relapse - ensure minimum 7-10 days of therapy 1
• Topical decongestants should not be used >3 days due to risk of rhinitis medicamentosa 1
• Reassess at 3-5 days if no improvement to avoid treatment failure 1, 2
• Avoid fluoroquinolones as first-line therapy - reserve for treatment failures, complicated sinusitis, or MDRSP 1
• Complete the full antibiotic course even after symptoms improve to prevent relapse 1

Watchful Waiting Option

For adults with uncomplicated acute bacterial sinusitis, watchful waiting without immediate antibiotics is appropriate when follow-up can be assured, with antibiotics started if no improvement by 7 days or worsening at any time. 1 The number needed to treat with antibiotics is 3-5 for persistent symptoms. 1