Augmentin for Sinus Infection
Augmentin (amoxicillin-clavulanate) is an excellent first-line antibiotic for acute bacterial sinusitis, with predicted clinical efficacy of 90-92% and bacteriologic efficacy of 97-99%. 1
When to Prescribe Augmentin
For adults with mild acute bacterial sinusitis who have not received antibiotics in the previous 4-6 weeks, use standard-dose amoxicillin-clavulanate 875/125 mg twice daily for 10-14 days. 1, 2
For adults with moderate disease or recent antibiotic exposure (within 4-6 weeks), escalate to high-dose amoxicillin-clavulanate 2000/125 mg (Augmentin XR) twice daily, which provides 91% clinical efficacy and 99% bacteriologic efficacy against resistant pathogens including penicillin-resistant S. pneumoniae. 1, 3, 4
For children, use high-dose amoxicillin-clavulanate 90 mg/6.4 mg per kg per day divided twice daily as first-line therapy, with predicted clinical efficacy of 91-92%. 5, 1
Why Augmentin Works
Augmentin demonstrates excellent microbiologic coverage against the primary sinusitis pathogens:
- 92.1% susceptibility against all S. pneumoniae strains (including penicillin-resistant strains) 1
- 98.3% susceptibility against H. influenzae 1
- 100% susceptibility against M. catarrhalis 1
The clavulanate component specifically overcomes beta-lactamase production in H. influenzae and M. catarrhalis, which has become increasingly prevalent. 3, 4
Critical 72-Hour Reassessment
Reassess all patients at 72 hours after initiating therapy. 5, 1 This timeframe is evidence-based: in clinical trials, 51% of placebo patients improved within 3 days, but only an additional 9% improved between days 3-10, indicating that patients who fail to improve by 72 hours are unlikely to respond without intervention change. 5
If the patient shows worsening symptoms or no improvement at 72 hours, switch to a respiratory fluoroquinolone (levofloxacin 500-750 mg daily or moxifloxacin 400 mg daily), which provides 92% clinical efficacy and 100% bacteriologic efficacy as second-line therapy. 1
Common Pitfalls to Avoid
Do not use macrolides (azithromycin, clarithromycin) as first-line therapy despite their convenience—they have only 77% predicted efficacy due to high resistance rates among S. pneumoniae. 1 While one older study showed comparable efficacy between clarithromycin and Augmentin 6, this predates the current resistance patterns.
Do not use trimethoprim-sulfamethoxazole (TMP/SMX) due to only 63.7% susceptibility against S. pneumoniae. 1
Do not underdose in moderate disease or recent antibiotic exposure—standard dosing will fail against resistant organisms. 1
Management in Penicillin Allergy
For non-Type I penicillin hypersensitivity (delayed rash, not anaphylaxis), use cefdinir, cefuroxime axetil, or cefpodoxime proxetil, which provide 83-87% efficacy. 1, 2
For Type I penicillin allergy (anaphylaxis, urticaria, angioedema), use respiratory fluoroquinolones (levofloxacin 500-750 mg daily in adults only), which provide 92% efficacy. 1 Fluoroquinolones should not be used in children due to concerns about developmental joint effects. 5
Duration of Therapy
Treat for 10-14 days total, or alternatively, continue therapy until the patient is symptom-free plus an additional 7 days. 5, 2 The latter approach individualizes treatment duration while ensuring a minimum 10-day course and avoiding prolonged therapy in asymptomatic patients unlikely to adhere. 5
Complete the full course even after symptom improvement to prevent relapse and resistance development. 7
Special Considerations
The high-dose formulations (Augmentin XR for adults, Augmentin ES-600 for children) were specifically developed to address drug-resistant S. pneumoniae with elevated penicillin MICs while maintaining coverage of beta-lactamase-producing organisms. 3, 4 These formulations use pharmacokinetically enhanced delivery to maintain therapeutic amoxicillin concentrations throughout the dosing interval. 4
In patients with mononucleosis, amoxicillin/ampicillin commonly causes a characteristic rash (not a true allergy), and if sinusitis symptoms are mild, consider discontinuing antibiotics entirely as 62-63% of cases resolve spontaneously. 8