What is the treatment for bacterial sinusitis with Augmentin (amoxicillin/clavulanic acid)?

Treatment of Bacterial Sinusitis with Augmentin (Amoxicillin/Clavulanate)

For adults with acute bacterial sinusitis, amoxicillin-clavulanate (Augmentin) 875 mg/125 mg twice daily for 5-10 days is the preferred first-line antibiotic, particularly when recent antibiotic use, moderate-to-severe disease, or risk factors for resistant bacteria are present. 1, 2

When to Choose Augmentin Over Plain Amoxicillin

Use amoxicillin-clavulanate instead of amoxicillin alone when any of the following apply:

• Recent antibiotic exposure (within the past 4-6 weeks) 1
• Moderate-to-severe symptoms (high fever ≥39°C, severe facial pain, systemic toxicity) 1, 2
• Risk factors for resistant bacteria:
  • Close contact with daycare facilities 1
  • Smoking or household smoker 1
  • Age >65 years 1
  • Comorbidities (diabetes, chronic cardiac/hepatic/renal disease) 1
  • Immunocompromised status 1
  • High community prevalence of β-lactamase-producing organisms 1
• Treatment failure with amoxicillin alone 2, 3
• Frontal, ethmoidal, or sphenoidal sinusitis (more serious anatomic locations) 2

Standard Dosing Regimen

Adults: Amoxicillin-clavulanate 875 mg/125 mg twice daily 1, 3, 4

Duration: 5-10 days, with most guidelines recommending treatment until symptom-free for 7 days (typically 10-14 days total) 1, 2, 3

• Shorter 5-7 day courses have comparable efficacy with fewer side effects 1, 2
• A 5-day course may be insufficient in patients with recurrent sinusitis or previous sinus surgery 5

Pediatric dosing: 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses 2, 3

High-Dose Formulation for Resistant Organisms

Consider high-dose amoxicillin-clavulanate (2000 mg/125 mg twice daily or 4 g/250 mg per day) when:

• Geographic regions with >10% prevalence of penicillin-nonsusceptible S. pneumoniae 1
• Severe infection with systemic toxicity 1
• High risk of multi-drug resistant pathogens 1

The evidence on high-dose formulations is mixed: older guidelines predicted 90-92% efficacy 1, but recent randomized trials showed no additional benefit over standard dosing and increased diarrhea rates 6. One trial found benefit only with immediate-release (not extended-release) high-dose formulations 7. Given this conflicting evidence and increased adverse effects, standard-dose amoxicillin-clavulanate remains the preferred initial approach for most patients. 1, 6

Monitoring and Treatment Failure Protocol

Reassess at 72 hours (3 days): 1, 2

• If no improvement or worsening, switch to alternative antibiotic or reevaluate diagnosis 1
• Second-line options for treatment failure:
  • Respiratory fluoroquinolones (levofloxacin 500-750 mg daily or moxifloxacin 400 mg daily) 1, 2
  • High-dose amoxicillin-clavulanate if not already used 1, 2
  • Ceftriaxone 1 g IM/IV daily for 5 days 1

By day 7-10: Most patients should show significant improvement 2, 3

Penicillin-Allergic Patients

For documented penicillin allergy: 1, 2

• Second-generation cephalosporins (cefuroxime-axetil) 1, 2
• Third-generation cephalosporins (cefpodoxime-proxetil, cefdinir) 1, 2
• Respiratory fluoroquinolones (levofloxacin, moxifloxacin) for severe allergy 1

Avoid azithromycin and other macrolides due to 20-25% resistance rates in S. pneumoniae and H. influenzae 2, 8

Adjunctive Therapies

• Intranasal corticosteroids are recommended as adjuncts to antibiotics 2, 9
• Short-term oral corticosteroids (e.g., dexamethasone 4 mg) may help in acute hyperalgic sinusitis (severe pain) or marked mucosal edema 2, 9
• Supportive measures: adequate hydration, analgesics, warm facial packs, sleeping with head elevated 2

Critical Pitfalls to Avoid

Do not treat viral upper respiratory infections with antibiotics - this contributes to resistance and provides no benefit 3, 9

Do not use macrolides (azithromycin, clarithromycin) as first-line therapy - resistance rates of 20-25% make them inappropriate 1, 2

Do not prescribe inadequate treatment duration - stopping antibiotics when symptoms improve but before completing 5-7 days risks relapse 2, 3

Do not use fluoroquinolones as routine first-line therapy - reserve these for treatment failures, complicated sinusitis, or penicillin allergy to prevent resistance 1, 2

Do not ignore treatment failure at 72 hours - persistent or worsening symptoms require antibiotic change or diagnostic reevaluation 1, 2

FDA-Approved Indication

Amoxicillin-clavulanate is FDA-approved for sinusitis caused by β-lactamase-producing strains of H. influenzae and M. catarrhalis, as well as ampicillin-susceptible organisms including most S. pneumoniae strains 4