What should be the next step in managing a patient with persistent sinusitis, conjunctivitis, and cough after five days of amoxicillin‑clavulanate (Augmentin) without improvement?

Switch to a Respiratory Fluoroquinolone or High-Dose Amoxicillin-Clavulanate

After failing both amoxicillin and standard-dose Augmentin, you should immediately switch to either a respiratory fluoroquinolone (levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily for 10 days) or high-dose amoxicillin-clavulanate (2 g/125 mg twice daily for 10 days), as these provide 90-92% predicted clinical efficacy against drug-resistant Streptococcus pneumoniae and β-lactamase-producing organisms. 1

Why the Initial Antibiotics Failed

Your patient's lack of response to both amoxicillin 875 mg and standard Augmentin suggests one of three scenarios:

• β-lactamase-producing organisms (Haemophilus influenzae or Moraxella catarrhalis) that weren't adequately covered by plain amoxicillin 1
• Drug-resistant Streptococcus pneumoniae requiring higher antibiotic concentrations 1
• This may not be bacterial sinusitis at all—98-99.5% of acute rhinosinusitis is viral and resolves spontaneously within 7-10 days 1

The conjunctivitis is particularly important here: purulent conjunctivitis accompanying sinusitis symptoms suggests a bacterial complication requiring antibiotic therapy. 2

Recommended Next Steps

First: Confirm This Is Actually Bacterial Sinusitis

Before escalating antibiotics, verify the patient meets at least one of these criteria 1:

• Persistent symptoms ≥10 days without improvement (purulent nasal discharge with obstruction or facial pain/pressure)
• Severe symptoms ≥3-4 consecutive days (fever ≥39°C with purulent discharge and facial pain)
• "Double sickening"—initial improvement followed by worsening after 5-6 days

If symptoms have lasted less than 10 days and aren't severe, this is likely viral and antibiotics won't help. 1

Second: Choose Your Second-Line Antibiotic

Option 1 (Preferred): Respiratory Fluoroquinolone 1

• Levofloxacin 500 mg once daily for 10 days OR
• Moxifloxacin 400 mg once daily for 10 days
• Predicted efficacy: 90-92% against all major sinusitis pathogens including multidrug-resistant S. pneumoniae 1
• Excellent coverage of β-lactamase-producing H. influenzae and M. catarrhalis 1

Option 2: High-Dose Amoxicillin-Clavulanate 1

• 2 g amoxicillin/125 mg clavulanate twice daily for 10 days
• Provides enhanced coverage against drug-resistant S. pneumoniae 1
• Covers β-lactamase-producing organisms 1
• Warning: Diarrhea occurs in 40-43% of patients, with severe diarrhea in 7-8% 1

The fluoroquinolone is often preferred at this stage because it has fewer gastrointestinal side effects and once-daily dosing improves compliance. 3

Essential Adjunctive Therapies (Add These Regardless of Antibiotic Choice)

These are not optional—they significantly improve outcomes:

Intranasal Corticosteroids (Strong Evidence) 1

• Mometasone, fluticasone, or budesonide twice daily
• Reduces mucosal inflammation and accelerates symptom resolution
• Multiple randomized controlled trials support this recommendation
• Should be started immediately alongside antibiotics

Saline Nasal Irrigation 1

• High-volume irrigation 2-3 times daily
• Provides symptomatic relief and clears mucus
• Enhances sinus drainage

Pain Management 1

• Acetaminophen or ibuprofen for facial pain and fever
• Address pain immediately—don't wait for antibiotics to work

Critical Reassessment Timeline

Day 3-5 of New Antibiotic: 1

• If no improvement, this constitutes treatment failure
• Consider imaging (CT scan) to exclude complications or alternative diagnosis
• Refer to ENT if not already done

Day 7 of New Antibiotic: 1

• By this point, 86-91% of patients should show significant improvement
• If symptoms persist or worsen, immediately evaluate for complications:
  • Orbital cellulitis (periorbital swelling, vision changes)
  • Meningitis (severe headache, neck stiffness, altered mental status)
  • Brain abscess (focal neurologic signs)

Any worsening at any time = urgent reassessment 1

What NOT to Do

Don't Use These Antibiotics 1

• Azithromycin or other macrolides: 20-25% resistance rates for both S. pneumoniae and H. influenzae
• Trimethoprim-sulfamethoxazole: 50% resistance in S. pneumoniae, 27% in H. influenzae
• First-generation cephalosporins (cephalexin): Inadequate coverage of H. influenzae (50% produce β-lactamase)
• Doxycycline: 20-25% predicted bacteriologic failure rate

Don't Continue Ineffective Therapy 1

• Waiting beyond 3-5 days to change antibiotics in non-responders delays effective treatment and may allow complications to develop
• The 3-5 day reassessment is specifically designed to catch early failures

When to Refer to ENT

Refer immediately if any of the following occur 1:

• No improvement after 7 days of appropriate second-line fluoroquinolone therapy
• Worsening symptoms at any point during treatment
• Suspected complications (severe headache, visual changes, periorbital swelling, altered mental status)
• Recurrent sinusitis (≥3 episodes per year)—requires evaluation for underlying allergic rhinitis, immunodeficiency, or anatomic abnormalities

Special Consideration: The Conjunctivitis Component

The presence of purulent conjunctivitis alongside sinusitis symptoms is a recognized sign of bacterial complication in the French guidelines. 2 This supports the decision to use antibiotics rather than watchful waiting, but the conjunctivitis itself may require additional topical therapy—consider ophthalmology consultation if it doesn't improve with systemic antibiotics.

Treatment Duration

Continue the chosen antibiotic for 10 days total or until symptom-free for 7 consecutive days (typically 10-14 days overall). 1 Recent evidence supports shorter 5-7 day courses for uncomplicated cases, but given this patient's treatment failures, a full 10-day course is warranted. 1