Amoxicillin-Clavulanate (Augmentin) for Sinusitis: When It Works & Resistance Concerns

Amoxicillin-clavulanate (amoxicillin + β-lactamase inhibitor clavulanate) is a first-line antibiotic for acute bacterial rhinosinusitis (ABRS) when antibiotics are warranted.

Indications for Antibiotics in Sinusitis (IDSA Guidelines)

• Persistent symptoms ≥10 days without improvement
• Severe onset: high fever (≥39°C/102°F) + purulent discharge/facial pain ≥3–4 days
• Worsening after initial improvement ("double sickening")

Why Augmentin Over Amoxicillin Alone?

• ~30–50% of H. influenzae and M. catarrhalis produce β-lactamase
• S. pneumoniae resistance via altered PBPs (clavulanate doesn't help)
• Clavulanate extends spectrum to β-lactamase producers

Dosing (Adults)

• Standard: 500/125 mg TID or 875/125 mg BID × 5–7 days (IDSA: 5–7 days sufficient)
• High-dose: 2000/125 mg BID (if resistant S. pneumoniae suspected)
• Pediatric: 45 mg/kg/day amoxicillin component divided BID

Resistance & Stewardship

• Rising S. pneumoniae resistance (non-β-lactamase mediated)
• ESBL-producing Gram-negatives (rare in sinusitis)
• Use only when bacterial infection likely; avoid for viral URI
• Consider culture if immunocompromised, treatment failure, nosocomial

Alternatives

• Doxycycline (if penicillin-allergic, non-type I)
• Respiratory fluoroquinolone (levofloxacin, moxifloxacin) — reserve for failures/allergy
• TMP-SMX, macrolides — high resistance, not recommended

Adjuncts

• Intranasal corticosteroids (reduce inflammation)
• Saline irrigation (mechanical clearance)
• Decongestants (short-term, oral or topical)
• Analgesics

Most sinusitis is viral—antibiotics only for confirmed bacterial cases.