What is the first line treatment for sinusitis?

First-Line Treatment for Sinusitis

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 7-10 days is the preferred first-line antibiotic for acute bacterial sinusitis in adults, though antibiotics should only be started when bacterial infection is confirmed by specific clinical criteria. 1, 2

When to Start Antibiotics (Critical Decision Point)

Most acute rhinosinusitis (98-99.5%) is viral and resolves spontaneously within 7-10 days without antibiotics. 1 Antibiotics are indicated only when one of three patterns is present:

• Persistent symptoms: Nasal discharge or cough lasting ≥10 days without improvement 1, 2
• Severe symptoms: Fever ≥39°C with purulent nasal discharge for ≥3 consecutive days 1, 2
• "Double sickening": Worsening symptoms after initial improvement from a viral upper respiratory infection 1, 2

Do not prescribe antibiotics for symptoms lasting <10 days unless severe symptoms are present, as this contributes to antimicrobial resistance without clinical benefit. 1

First-Line Antibiotic Selection

Standard First-Line Choice

• Amoxicillin-clavulanate 875 mg/125 mg twice daily is preferred over plain amoxicillin due to increasing prevalence of β-lactamase-producing organisms (H. influenzae and M. catarrhalis). 1, 2
• Plain amoxicillin 500 mg twice daily (mild disease) or 875 mg twice daily (moderate disease) remains acceptable for uncomplicated cases without recent antibiotic exposure. 1, 2
• Treatment duration: 7-10 days, typically continuing until symptom-free for 7 days (total 10-14 days). 1, 2

For Penicillin-Allergic Patients

Classify the allergy type first to guide safe antibiotic selection. 1

• Non-anaphylactic reactions (rash, mild reactions): Second- or third-generation cephalosporins are safe and recommended. 1
  • Cefuroxime-axetil (second-generation) 1, 2
  • Cefpodoxime-proxetil or cefdinir (third-generation, superior activity against H. influenzae) 1, 2
• Severe Type I hypersensitivity (anaphylaxis): Respiratory fluoroquinolones (levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily for 10 days) provide 90-92% predicted clinical efficacy. 1, 3

Avoid azithromycin and other macrolides as first-line therapy due to resistance rates of 20-25% for both S. pneumoniae and H. influenzae. 1

Symptomatic Treatment (Appropriate for All Patients)

For viral rhinosinusitis or while awaiting bacterial confirmation:

• Analgesics: Acetaminophen or NSAIDs for pain and fever relief 1, 4
• Intranasal corticosteroids: Reduce mucosal inflammation, alleviate symptoms, and potentially decrease need for antibiotics 1, 4
• Saline nasal irrigation: Provides symptomatic relief and promotes drainage 1, 4
• Oral decongestants: Symptomatic relief (pseudoephedrine) 1, 4
• Topical decongestants: Maximum 3 days use to prevent rhinitis medicamentosa (rebound congestion) 2, 4

Treatment Failure Protocol

Reassess at 3-5 days: If no improvement, switch antibiotics or re-evaluate diagnosis. 1, 2

• Switch to high-dose amoxicillin-clavulanate (4 g amoxicillin/250 mg clavulanate per day) for enhanced coverage against drug-resistant S. pneumoniae. 1
• Alternative: Respiratory fluoroquinolones (levofloxacin 500-750 mg once daily or moxifloxacin 400 mg once daily) for treatment failures, providing excellent coverage against multi-drug resistant organisms. 1, 3

Pediatric Dosing Considerations

• Standard therapy: Amoxicillin 45 mg/kg/day in 2 divided doses 1
• High-risk children (age <2 years, daycare attendance, recent antibiotic use, high local resistance): Amoxicillin 80-90 mg/kg/day in 2 divided doses OR amoxicillin-clavulanate 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses 1

Critical Pitfalls to Avoid

• Inadequate treatment duration leads to relapse—complete the full 7-10 day course even after symptoms improve. 1, 2
• Reserve fluoroquinolones as second-line therapy to prevent resistance development; use only for complicated sinusitis, first-line treatment failure, or severe penicillin allergy. 1, 2
• Watchful waiting is appropriate for uncomplicated cases when follow-up can be assured—start antibiotics only if no improvement by 7 days or worsening at any time. 1
• Number needed to treat with antibiotics is 10-15 to get one additional person better after 7-15 days, emphasizing the importance of proper patient selection. 1