After a 20‑day course of Augmentin (amoxicillin/clavulanate) for sinus infection, I still have lingering sinus pressure; what should I try next?

Add Intranasal Corticosteroids and Consider Switching to a Different Antibiotic Class

Your situation represents a "partial response" to treatment—you've improved but aren't back to normal after 20 days of Augmentin, which is longer than the typical 10-14 day course for acute sinusitis. Based on established guidelines, you should add intranasal corticosteroid spray and potentially switch antibiotics if symptoms don't fully resolve.

Immediate Next Steps

Start a nasal corticosteroid spray (like fluticasone or mometasone) twice daily. 1 The guidelines specifically state that nasal corticosteroids are helpful when patients fail to respond to initial treatment, even though their efficacy hasn't been definitively proven in acute sinusitis. Given your prolonged symptoms with residual pressure, this adjunctive therapy is reasonable.

For the antibiotic question: Since you've already been on Augmentin (amoxicillin-clavulanate) for 20 days—well beyond the standard course—continuing the same antibiotic is unlikely to provide additional benefit. 1

Antibiotic Decision Algorithm

If you're going to continue antibiotics, switch to a different class:

• First consideration: A respiratory fluoroquinolone (levofloxacin or moxifloxacin) for 10-14 days 1, 2
• Alternative: A cephalosporin like cefuroxime, cefpodoxime, or cefdinir 1

The guidelines specifically recommend these alternatives for sinusitis that fails to improve after 21-28 days of initial antibiotic treatment, which describes your situation. 1

However, there's an important caveat: Recent high-quality evidence from 2026 shows that amoxicillin alone (without clavulanate) is equally effective as Augmentin for acute sinusitis, with lower rates of secondary infections like yeast infections and C. difficile. 3 Additionally, a 2017 placebo-controlled trial found that adding antibiotics to topical steroids provided no additional benefit for acute exacerbations of chronic rhinosinusitis. 4

Consider Whether You Actually Need More Antibiotics

Given that you've already had 20 days of antibiotics with major symptom improvement, you may not need another antibiotic course at all. Instead:

1. Start intranasal corticosteroid spray (most important intervention) 1
2. Continue supportive measures: saline nasal irrigation, adequate hydration, warm facial packs, steamy showers, sleep with head elevated 1
3. Consider a short-term oral decongestant (pseudoephedrine) if nasal congestion is prominent 5
4. Wait 7-10 more days while using the above measures

When to Pursue Further Evaluation

You should get further workup if:

• Symptoms worsen or don't improve after another 7-10 days with nasal steroids
• You develop high fever, severe headache, facial swelling, or vision changes (seek immediate care) 1
• This is your third or more episode of sinusitis in a year (recurrent sinusitis) 1

At that point, consider:

• CT scan of sinuses 1
• Evaluation for underlying causes: allergic rhinitis, structural abnormalities (deviated septum), nasal polyps, or immunodeficiency 1
• Referral to an allergist-immunologist or ENT specialist 1

Common Pitfall to Avoid

The biggest mistake would be continuing the same antibiotic indefinitely or repeatedly cycling through multiple antibiotics without addressing the underlying inflammation. Sinusitis that persists beyond 21-28 days may be due to resistant bacteria, but it's more commonly due to inadequately treated inflammation, underlying allergies, or structural issues—none of which respond to more antibiotics. 1 The nasal steroid addresses the inflammatory component that antibiotics cannot.