In a patient with uncomplicated acute bacterial sinusitis of the nose who has no penicillin allergy, normal renal function, and is not pregnant, is Augmentin (amoxicillin‑clavulanate) or doxycycline the preferred treatment?

Augmentin is the preferred first-line antibiotic for acute bacterial sinusitis in adults

For a patient with uncomplicated acute bacterial sinusitis and no penicillin allergy, amoxicillin-clavulanate (Augmentin) is the preferred treatment over doxycycline. 1, 2, 1

Rationale for Augmentin as First-Line

The 2012 IDSA guidelines explicitly recommend amoxicillin-clavulanate as the preferred empirical agent for acute bacterial rhinosinusitis (ABRS), with doxycycline listed only as an alternative option 1, 2, 1. This recommendation is based on coverage of the most common resistant pathogens:

• Ampicillin-resistant Haemophilus influenzae (10-42% β-lactamase positive)
• Ampicillin-resistant Moraxella catarrhalis (nearly 100% β-lactamase positive)
• Penicillin-nonsusceptible Streptococcus pneumoniae (10-15% nationally, up to 50-60% in some regions)

The clavulanate component specifically inhibits β-lactamase-producing organisms that would otherwise resist amoxicillin alone 3.

When to Use Doxycycline Instead

Doxycycline should be reserved for:

• Patients with documented penicillin allergy 1, 4
• Patients who cannot tolerate β-lactams

In these cases, doxycycline or a respiratory fluoroquinolone (levofloxacin, moxifloxacin) are appropriate alternatives 1, 4.

Recent High-Quality Evidence

A 2026 large retrospective cohort study (521,244 patients) found no difference in treatment failure rates between amoxicillin-clavulanate and amoxicillin alone (3.0% vs 3.1%) 5. However, this study compared amoxicillin-clavulanate to amoxicillin alone—not to doxycycline. The study actually supports using narrower-spectrum therapy when appropriate, but doxycycline has even less robust evidence for ABRS compared to β-lactams.

Important Caveats

First, Confirm Bacterial Sinusitis

Only prescribe antibiotics when bacterial infection is likely 1:

• Symptoms persistent >10 days without improvement
• Severe symptoms: fever >39°C (102.2°F) + purulent nasal discharge + facial pain for ≥3 consecutive days
• "Double sickening": worsening after initial improvement

Most acute rhinosinusitis is viral and self-limited. The number needed to treat with antibiotics is 18, while the number needed to harm is 8 1.

Dosing Matters

Use high-dose amoxicillin-clavulanate (2g orally twice daily) for patients at high risk of resistant organisms 2, 4:

• Recent antibiotic use (within 30 days)
• Age >65 years
• Severe infection
• Geographic areas with >10% penicillin-nonsusceptible S. pneumoniae

Treatment Duration

• Adults: 5-7 days is sufficient 2, 4
• Children: 10-14 days recommended 2, 3

Adjunctive Therapy

Add intranasal saline irrigation and intranasal corticosteroids to reduce symptoms and potentially decrease antibiotic need 1, 2. Avoid decongestants and antihistamines—they don't help 2.

Bottom Line

Augmentin (amoxicillin-clavulanate) is superior to doxycycline for uncomplicated acute bacterial sinusitis because it provides better coverage of the three main pathogens, particularly resistant strains. Doxycycline should only be used when β-lactams are contraindicated. However, remember that most "sinus infections" are viral and don't require any antibiotic at all—reserve treatment for patients meeting specific clinical criteria to avoid unnecessary harm and antibiotic resistance.