What fluoroquinolone (FLQ) to use for acute sinusitis after Augmentin (amoxicillin-clavulanate) failure?

Fluoroquinolone Selection After Augmentin Failure in Acute Sinusitis

Use levofloxacin 500 mg once daily for 10-14 days or moxifloxacin 400 mg once daily for 10 days as the fluoroquinolone of choice after Augmentin failure in acute bacterial sinusitis. 1, 2, 3

Recommended Fluoroquinolones

First-Line Respiratory Fluoroquinolones

• Levofloxacin and moxifloxacin are the only fluoroquinolones recommended for sinusitis because they have adequate activity against Streptococcus pneumoniae, the most common bacterial pathogen. 1, 4, 5
• These respiratory fluoroquinolones should be reserved specifically for treatment failure of first-line antibiotics like amoxicillin-clavulanate, or for complicated sinusitis (frontal, ethmoidal, or sphenoidal). 1

Specific Dosing Regimens

• Levofloxacin: 500 mg orally once daily for 10-14 days 1, 2
• Moxifloxacin: 400 mg orally once daily for 10 days 1, 3
• Both regimens have demonstrated clinical success rates of 83-93% in acute bacterial sinusitis. 6, 7, 8

Critical Caveat: Ciprofloxacin is NOT Appropriate

• Ciprofloxacin should never be used for sinusitis because it has inadequate coverage against S. pneumoniae, with an AUC-to-MIC ratio of only 10-20 when the target should be 25-30. 5
• Only respiratory fluoroquinolones (levofloxacin, moxifloxacin) have sufficient pneumococcal activity for respiratory tract infections. 5

When to Use Fluoroquinolones

Appropriate Indications

• After documented failure of amoxicillin-clavulanate (Augmentin) with bacteriological and/or radiological confirmation when possible. 1
• Complicated sinusitis involving frontal, fronto-ethmoidal, or sphenoidal sinuses where complications are more likely. 1
• Penicillin-allergic patients with moderate to severe disease or recent antibiotic use. 4

Reserve Use Strategy

• Fluoroquinolones should be reserved for these specific situations to minimize resistance development in gram-negative organisms, staphylococci, and pneumococci. 5
• The FDA labels for both levofloxacin and moxifloxacin emphasize that these agents should only be used when no alternative treatment options exist for acute bacterial sinusitis. 2, 3

Clinical Efficacy Data

Levofloxacin Performance

• Clinical success rates of 88-94% when compared to amoxicillin-clavulanate in acute sinusitis. 6, 7
• Superior tolerability profile with only 7.4% drug-related adverse events versus 21.2% with amoxicillin-clavulanate. 6
• Achieves high tissue concentrations in sinus mucosa exceeding plasma levels. 9

Moxifloxacin Performance

• Clinical cure rates of 91.4% in acute bacterial sinusitis with 10-day therapy. 2
• Comparable efficacy to levofloxacin with similar tolerability profiles. 3

Important Safety Warnings

Black Box Warnings Apply to Both Agents

• Risk of tendinitis and tendon rupture, particularly Achilles tendon, especially in patients with renal dysfunction. 4, 3
• Peripheral neuropathy that may be irreversible. 3
• Central nervous system effects including seizures and psychiatric disturbances. 3
• Exacerbation of myasthenia gravis - avoid in patients with known myasthenia gravis. 3

Moxifloxacin-Specific Warnings

• QT interval prolongation with isolated cases of torsade de pointes reported - avoid in patients with known QT prolongation, hypokalemia, hypomagnesemia, clinically significant bradycardia, or acute myocardial ischemia. 3
• Avoid concomitant use with other QT-prolonging medications. 3

Common Adverse Events

• Most common reactions (≥3%) include nausea, diarrhea, headache, and dizziness. 2, 3
• Drug-related adverse events occur in 7-22% of patients, significantly lower than with amoxicillin-clavulanate. 6

Alternative Non-Fluoroquinolone Options

If you want to avoid fluoroquinolones entirely after Augmentin failure:

• Second or third-generation cephalosporins: cefuroxime-axetil, cefpodoxime-proxetil, or cefdinir for 10-14 days. 1, 8
• Doxycycline for mild disease in penicillin-allergic patients. 4
• These alternatives showed comparable efficacy (72-83% cure rates) to fluoroquinolones in clinical trials. 8, 10

Treatment Duration and Follow-Up

• Standard duration is 10-14 days for maxillary sinusitis with fluoroquinolones. 1, 2
• Shorter 5-day courses of levofloxacin 750 mg have shown comparable efficacy but are not standard for treatment failures. 2
• If no clinical improvement occurs within 3-5 days, consider imaging studies and possible ENT referral for complicated disease. 1