What is the recommended dose of Augmentin (amoxicillin-clavulanate) for treating sinusitis?

Augmentin Dosing for Sinusitis

Standard Adult Dosing Recommendation

For adults with acute bacterial sinusitis, the recommended dose of Augmentin is 875 mg/125 mg twice daily for 10-14 days. 1, 2, 3

Dosing Algorithm by Clinical Scenario

Mild Disease (No Recent Antibiotic Use)

• Augmentin 875/125 mg twice daily is appropriate for patients who have not received antibiotics in the previous 4-6 weeks 1, 4
• Alternative: Standard-dose amoxicillin alone (1.5-4 g/day) may be considered first-line, reserving Augmentin for treatment failures 1, 5
• Treatment duration: 10-14 days 1, 2, 5

Moderate-to-Severe Disease or Recent Antibiotic Exposure

• High-dose Augmentin: 2000 mg amoxicillin/125 mg clavulanate twice daily (or 90 mg/kg amoxicillin component, not exceeding 2 g every 12 hours) 1, 2, 5
• This high-dose regimen is specifically indicated for:
  • Antibiotic use within the past 4-6 weeks 1, 2
  • Suspected resistant organisms (β-lactamase-producing H. influenzae or resistant S. pneumoniae) 1, 5
  • Treatment failure with standard-dose amoxicillin 2, 5
  • Moderate-to-severe illness presentation 1, 5

Pediatric Dosing (≥12 Weeks Old)

• 45 mg/kg/day of amoxicillin component divided twice daily for otitis media, sinusitis, and lower respiratory tract infections 3
• For children weighing ≥40 kg, use adult dosing (875/125 mg twice daily) 1, 3
• Treatment duration: 7-10 days 1

Treatment Response Assessment

Evaluate clinical response at 72 hours (3 days). 1, 4

• If no improvement or worsening: Switch to alternative antibiotic (respiratory fluoroquinolone or high-dose Augmentin if not already used) or reevaluate diagnosis 1, 2
• If partial improvement: Continue full course of current antibiotic 2, 5
• If improved: Complete the full 10-14 day course 2, 5

Evidence Supporting Dosing Recommendations

The 875/125 mg twice-daily formulation demonstrates superior outcomes compared to alternatives. In chronic rhinosinusitis, this regimen showed faster symptom improvement at days 3-5 (81% vs 56%, P=0.014) and significantly lower clinical relapse rates (0% vs 8%, P=0.005) compared to cefuroxime 2.

Important caveat: A 2021 randomized trial found that high-dose amoxicillin/clavulanate (1750 mg amoxicillin twice daily) provided no additional benefit over standard-dose (875 mg twice daily) in adults with acute sinusitis, with both groups showing similar improvement rates at day 3 (44.3% vs 36.4%, P=0.35) 6. However, an earlier 2018 study using immediate-release high-dose formulation showed an 18% absolute improvement (52.4% vs 34.4%, P=0.04) at day 3, though with increased severe diarrhea (15.8% vs 4.8%) 7. Given this conflicting evidence and the increased side effect profile, standard-dose 875/125 mg twice daily remains the most appropriate initial choice for most patients.

Critical Pitfalls to Avoid

• Do NOT substitute two 250/125 mg tablets for one 500/125 mg tablet - they contain different ratios of clavulanate and are not equivalent 3
• Do NOT use the 875/125 mg dose in patients with severe renal impairment (GFR <30 mL/min) - reduce to 500/125 mg or 250/125 mg every 12-24 hours depending on severity 3
• Do NOT treat viral sinusitis with antibiotics - reserve antibiotics only for bacterial sinusitis meeting IDSA criteria (symptoms >10 days, severe symptoms, or worsening after initial improvement) 5, 4
• Do NOT use pediatric weight-based formulations in adolescents who can swallow adult tablets - this is unnecessary and more expensive 2

Penicillin-Allergic Patients

For patients with β-lactam allergies, alternatives include doxycycline, trimethoprim-sulfamethoxazole, or respiratory fluoroquinolones (levofloxacin, moxifloxacin), though these carry 20-25% bacteriologic failure rates 1, 4