What is the recommended dosing for Augmentin (amoxicillin-clavulanate) for a sinus infection?

Augmentin Dosing for Sinus Infection

Standard Dosing Recommendation

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

When to Use Augmentin vs. Plain Amoxicillin

Augmentin should be selected over plain amoxicillin in the following clinical scenarios:

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

For uncomplicated cases without these risk factors, plain amoxicillin remains first-line therapy. 1, 3

High-Dose Regimen for Resistant Organisms

When resistant pathogens are suspected or standard-dose therapy has failed, escalate to a high-dose regimen of 90 mg/kg of the amoxicillin component (maximum 2 g) every 12 hours. 1, 2

Important caveat: Recent high-quality evidence from a 2021 randomized trial found no benefit of high-dose over standard-dose amoxicillin-clavulanate in adults with acute sinusitis, with similar efficacy (44.3% vs 36.4% improvement at day 3, P=0.35) but comparable rates of severe diarrhea. 4 However, a 2018 trial showed that immediate-release high-dose formulations (1750 mg amoxicillin twice daily) provided faster improvement (52.4% vs 34.4% at day 3, P=0.04) compared to standard dosing, though with increased diarrhea risk (15.8% vs 4.8%). 5 Given this conflicting evidence, reserve high-dose therapy for documented treatment failures or confirmed resistant organisms rather than routine use.

Treatment Duration

• Standard course: 10-14 days 1, 2, 3
• Alternative approach: Continue treatment until symptom-free for 7 days 1, 2

The 10-14 day duration is supported by multiple guidelines and remains the standard of care. 1, 2, 3

Monitoring Treatment Response

Assess clinical response after 72 hours (3 days) of therapy. 1, 3

• If improving: Continue the full antibiotic course 1
• If no improvement or worsening: Switch to an alternative antibiotic or reevaluate the diagnosis 1, 3
• If partial response: Continue antibiotics for the full 10-14 day course 2

Alternatives for Penicillin-Allergic Patients

For patients with penicillin allergy:

• Cephalosporins (cefpodoxime, cefuroxime, or cefdinir) if no history of anaphylaxis 1, 3
• Doxycycline for non-severe reactions 1
• Respiratory fluoroquinolones (levofloxacin, moxifloxacin) for severe cases or treatment failures 1

Note that macrolides (azithromycin, clarithromycin) and TMP-SMX have higher bacteriologic failure rates of 20-25% and should be used cautiously. 3

Critical Pitfalls to Avoid

Do not treat viral sinusitis with antibiotics. This is the most common error and drives antibiotic resistance. 1, 3 Only prescribe antibiotics when bacterial sinusitis is diagnosed according to IDSA criteria (symptoms >10 days without improvement, severe symptoms with high fever ≥39°C and purulent discharge for 3-4 consecutive days, or worsening symptoms after initial improvement).

Do not allow incomplete courses. Stopping antibiotics early leads to incomplete bacterial eradication and potential relapse. 1, 3 Emphasize completing the full 10-14 day course even if symptoms resolve earlier.

Do not use standard-dose amoxicillin in high-resistance areas without considering Augmentin as first-line therapy. 3

Comparative Efficacy Data

European data from chronic rhinosinusitis studies showed that Augmentin 875/125 mg twice daily for 14 days demonstrated faster symptom improvement at days 3-5 compared to cefuroxime (81% vs 56%, P=0.014) and significantly lower clinical relapse rates at weeks 2-4 (0% vs 8%, P=0.005). 6 Diarrhea was the most common adverse effect in both groups, occurring comparably. 6