What is the recommended prescription treatment plan for acute bacterial sinusitis?

Prescription Treatment Plan for Acute Bacterial Sinusitis

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-7 days is the first-line antibiotic for adults with acute bacterial sinusitis, combined with intranasal corticosteroids twice daily. 1, 2, 3

Confirm the Diagnosis First

Before prescribing antibiotics, verify the patient meets one of three diagnostic criteria for bacterial (not viral) sinusitis: 1

• Persistent symptoms ≥10 days without improvement (nasal congestion, purulent discharge, facial pain/pressure) 1
• Severe symptoms for ≥3-4 consecutive days at illness onset (fever ≥39°C [102°F] AND purulent nasal discharge or facial pain) 1
• "Double sickening": worsening symptoms after 5-6 days of initial improvement from a viral URI (new fever, headache, or increased nasal discharge) 1

Critical pitfall: 98-99.5% of acute rhinosinusitis is viral and resolves spontaneously within 7-10 days—do not prescribe antibiotics for symptoms lasting <10 days unless severe criteria are met. 1, 2

First-Line Antibiotic Treatment

Adults Without Penicillin Allergy

Amoxicillin-clavulanate 875 mg/125 mg orally twice daily for 5-7 days is the preferred first-line agent due to coverage against β-lactamase-producing Haemophilus influenzae (20-30% prevalence) and Moraxella catarrhalis (12-28% prevalence). 1, 2, 3

• Plain amoxicillin is no longer recommended as first-line therapy due to high rates of β-lactamase-producing organisms. 2, 3
• Treatment duration: 5-7 days for uncomplicated cases in adults provides comparable efficacy to 10-14 days with fewer adverse effects. 1, 2

Pediatric Patients (≥3 months)

High-dose amoxicillin-clavulanate 80-90 mg/kg/day of the amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses for 10-14 days is recommended for children with risk factors (age <2 years, daycare attendance, recent antibiotic use within 4-6 weeks, or high local resistance rates). 1, 2, 4

• For children without risk factors: standard-dose amoxicillin 45 mg/kg/day in 2 divided doses for 10-14 days. 1, 4
• Longer treatment duration (10-14 days) is still recommended in children compared to adults. 1

Penicillin-Allergic Patients

Non-Severe Allergy (Rash, Delayed Reaction)

Second- or third-generation cephalosporins are safe and effective, as the risk of serious cross-reactivity is negligible: 1, 2

• Cefuroxime-axetil (second-generation): 250-500 mg twice daily for 10 days 1, 2
• Cefpodoxime-proxetil (third-generation): 200-400 mg twice daily for 10 days 1, 2
• Cefdinir (third-generation): 300 mg twice daily for 10 days 1, 2

Severe Type I Hypersensitivity (Anaphylaxis)

Respiratory fluoroquinolones are the treatment of choice: 2, 3

• Levofloxacin 500 mg once daily for 10-14 days (preferred) 2, 5
• Moxifloxacin 400 mg once daily for 10 days (alternative) 2

Do not use: 2, 4

• Azithromycin or clarithromycin (resistance rates 20-40% for S. pneumoniae) 2, 4, 6
• Trimethoprim-sulfamethoxazole (resistance rates 50% for S. pneumoniae, 27% for H. influenzae) 2, 4

Second-Line Treatment for Treatment Failure

If no improvement after 3-5 days (adults) or 72 hours (children), switch to a respiratory fluoroquinolone: 1, 2

• Levofloxacin 500-750 mg once daily for 10-14 days provides 90-92% predicted clinical efficacy and 100% microbiologic eradication of S. pneumoniae, including multi-drug resistant strains. 2, 5
• Alternative: Moxifloxacin 400 mg once daily for 10 days 2

For children who fail initial therapy, switch to high-dose amoxicillin-clavulanate (if not already used) or consider ceftriaxone 50 mg/kg IM/IV once daily for 5 days if unable to tolerate oral medications. 1, 4

Mandatory Adjunctive Therapies

Intranasal Corticosteroids (Strongly Recommended)

Add intranasal corticosteroids to antibiotic therapy in ALL patients, particularly those with allergic rhinitis: 1, 2

• Mometasone, fluticasone, or budesonide: 2 sprays per nostril twice daily 2
• Reduces mucosal inflammation and improves symptom resolution 1
• Benefits appear after 15 days of use 1

Supportive Measures

• Intranasal saline irrigation (physiologic or hypertonic): relieves symptoms and removes mucus 1
• Analgesics (acetaminophen or ibuprofen): for pain and fever relief 1
• Adequate hydration and sleeping with head elevated 4

What NOT to Use

Do not prescribe: 1

• Oral or topical decongestants (no proven benefit) 1
• Oral antihistamines (no proven benefit unless underlying allergic rhinitis) 1

Monitoring and Reassessment

Reassess at 3-5 days (adults) or 72 hours (children): 1, 2

• If worsening or no improvement: Switch to second-line antibiotic (fluoroquinolone) or re-evaluate diagnosis 1
• If improving: Complete the full antibiotic course (5-7 days adults, 10-14 days children) 1, 2

When to Refer to a Specialist

Refer to otolaryngology, infectious disease, or allergy specialist if: 1

• Symptoms refractory to two courses of appropriate antibiotics 1
• Suspected complications (orbital cellulitis, meningitis, brain abscess) 1
• Immunocompromised patients who continue to deteriorate 1
• Recurrent sinusitis (≥3 episodes per year) with clearing between episodes 1, 4

Watchful Waiting Option (Adults Only)

For uncomplicated acute bacterial sinusitis in adults, watchful waiting without immediate antibiotics is appropriate when follow-up can be assured: 1, 3

• Provide antibiotic prescription but instruct patient to fill only if no improvement by 7 days or worsening at any time 1
• Antibiotics provide only modest benefit: number needed to treat is 10-15 to get one additional person better after 7-15 days 1
• Most patients (90%) improve naturally within 7-15 days 1

Critical Pitfalls to Avoid

• Never use plain amoxicillin as first-line therapy—β-lactamase-producing organisms render it ineffective in 20-30% of cases 2, 3
• Never prescribe antibiotics for viral rhinosinusitis lasting <10 days without severe symptoms—this contributes to resistance without benefit 1, 2
• Never continue ineffective antibiotics beyond 3-5 days—failure to switch therapy leads to prolonged illness and complications 1, 2
• Never use azithromycin or clarithromycin as first-line therapy due to resistance rates exceeding 20-40% 2, 4
• Never routinely cover for MRSA during initial empiric therapy—current data do not support this practice 1
• Never use first-generation cephalosporins (cephalexin)—they lack adequate coverage against H. influenzae 4