Antibiotic Treatment for Acute Bacterial Sinusitis

First-Line Treatment Selection

The American College of Physicians recommends amoxicillin-clavulanate as the preferred first-line antibiotic for acute bacterial sinusitis in adults, dosed at standard strength (875 mg/125 mg twice daily) for 7-10 days 1, 2
Amoxicillin-clavulanate (875 mg/125 mg twice daily) is recommended as the primary choice due to increasing prevalence of beta-lactamase-producing organisms like H. influenzae and M. catarrhalis 3
Plain amoxicillin (500 mg twice daily for mild infections, 875 mg twice daily for more severe) remains acceptable for uncomplicated cases in patients without recent antibiotic exposure 1
The treatment duration is 7-10 days until symptom-free for 7 days 1, 4

The anatomic site of infection determines antibiotic selection and urgency, with maxillary sinusitis being the most common location 4
For maxillary sinusitis, standard first-line antibiotics such as amoxicillin-clavulanate are recommended 4, 1
For frontal, ethmoidal, or sphenoidal sinusitis, fluoroquinolones (levofloxacin 500-750 mg daily or moxifloxacin 400 mg daily) are reserved due to higher complication risk 4, 1

If no improvement occurs within 3-5 days, switch to high-dose amoxicillin-clavulanate (if not already used) 1, 2
Consider respiratory fluoroquinolones (levofloxacin 750 mg daily for 5 days or 500 mg daily for 10 days; moxifloxacin 400 mg daily for 10 days) for treatment failure 4, 1

Intranasal corticosteroids are recommended as an adjunct to antibiotic therapy 1, 2
Short-term oral corticosteroids are recommended for acute hyperalgic sinusitis (severe pain) or marked mucosal edema 4, 1

For pediatric patients, amoxicillin 45 mg/kg/day (standard) or 80-90 mg/kg/day (high-dose for resistant S. pneumoniae) in 2 divided doses is recommended 5, 1
For recurrent sinusitis, evaluate for underlying factors such as allergic rhinitis, immunodeficiency, or anatomic abnormalities, and consider referral to an allergist-immunologist or otolaryngologist 1, 2