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

Amoxicillin-Clavulanate Dosing for Sinusitis

Recommended Dose and Duration

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

Standard Dosing Protocol

• Standard adult dose: 875 mg amoxicillin/125 mg clavulanate twice daily 1, 2, 4
• Treatment duration: 10-14 days is the recommended course 1, 2, 3
• Some guidelines suggest continuing treatment until the patient has been symptom-free for 7 days 1, 2, 3

When to Use Amoxicillin-Clavulanate vs. Plain Amoxicillin

Amoxicillin-clavulanate should be selected over plain amoxicillin in these specific scenarios:

• Moderate to severe illness at presentation 1, 2
• Recent antibiotic use within the previous 4-6 weeks 1, 2
• Treatment failure after 3-5 days of amoxicillin therapy 2, 3
• High prevalence of β-lactamase-producing H. influenzae in your region 1, 2
• Areas with high antibiotic resistance patterns 2, 3

High-Dose Regimen Considerations

• For suspected resistant organisms or treatment failure, a high-dose regimen of 90 mg/kg amoxicillin component (not to exceed 2 g every 12 hours) can be considered 2, 3
• However, recent high-quality evidence suggests limited benefit: A 2021 randomized trial found no significant difference between high-dose (1750 mg amoxicillin twice daily) and standard-dose (875 mg twice daily) regimens, with 44.3% vs 36.4% reporting major improvement at day 3 (P=0.35) 5
• High-dose regimens may increase severe diarrhea risk (7.7% vs 7.0% in standard dose) without clear efficacy benefit 5

Treatment Response Assessment

• Evaluate response after 72 hours (3 days) of treatment 1, 2
• If no improvement or worsening after 72 hours, switch to an alternative antibiotic or reevaluate the diagnosis 1, 2, 3
• Patients with partial response should continue antibiotics for the full 10-14 day course 2, 3

Critical Pitfalls to Avoid

• Do not treat viral sinusitis with antibiotics - this is the most common error and contributes to antibiotic resistance 1, 2
• Do not use 250 mg/125 mg tablets interchangeably with 500 mg/125 mg or 875 mg/125 mg formulations, as the clavulanate ratios differ 4
• Avoid standard-dose amoxicillin alone in areas with high resistance patterns, as this may lead to treatment failure 1
• Do not prescribe incomplete courses - failure to complete the full 10-14 day course can lead to incomplete eradication and relapse 1, 2

Alternative Options for Penicillin Allergy

• Second or third-generation cephalosporins (cefpodoxime, cefuroxime, cefdinir) if no history of anaphylaxis 1, 3
• Doxycycline as an alternative 1
• Respiratory fluoroquinolones for severe cases or treatment failures 2
• Note that alternatives like TMP/SMX, azithromycin, and clarithromycin have higher bacteriologic failure rates (20-25%) 1

Renal Dosing Adjustments

• GFR <30 mL/min: Do not use the 875 mg/125 mg dose 4
• GFR 10-30 mL/min: Use 500 mg/125 mg or 250 mg/125 mg every 12 hours 4
• GFR <10 mL/min: Use 500 mg/125 mg or 250 mg/125 mg every 24 hours 4
• Hemodialysis patients: Give 500 mg/125 mg or 250 mg/125 mg every 24 hours, with an additional dose during and at the end of dialysis 4

Evidence on Treatment Duration

While 10-14 days remains the standard recommendation 1, 2, 3, one study evaluated 5-day vs 10-day courses and found success rates of 80% vs 85%, respectively, but the durations could not be considered equivalent 6. Patients with risk factors such as recurrent sinusitis or previous sinus surgery should receive the full 10-14 day course rather than shortened therapy 6.