Antibiotic Treatment for Acute Bacterial Sinusitis

Initial Antibiotic Selection

The American Academy of Otolaryngology recommends amoxicillin with or without clavulanate as the first-line antibiotic for most adults with acute bacterial sinusitis, prescribed for 5 to 10 days 1, 2
Amoxicillin alone (1.5-4 g/day) is appropriate for mild disease in patients without recent antibiotic use, providing 87-88% clinical efficacy and 91-92% bacteriologic efficacy against primary pathogens 3, 4
Amoxicillin-clavulanate (875 mg twice daily) should be chosen over amoxicillin alone in patients with recent antibiotic use, moderate to severe symptoms, age >65 years, diabetes, or other chronic comorbidities, immunocompromised status, high local prevalence of penicillin-resistant S. pneumoniae, close contact with daycare children, or smoking 1

For patients with true penicillin allergy, the American Academy of Otolaryngology recommends respiratory fluoroquinolones as the preferred alternative, with options including levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily for 5-10 days 1, 4
Doxycycline 100 mg twice daily is an alternative, with 81% clinical efficacy, but lower bacteriologic efficacy at 80% 3, 4

The American Academy of Otolaryngology recommends a treatment duration of 5-7 days, which is as effective as 10 days for most patients and causes fewer adverse effects 1, 2
Standard duration remains 10 days for severe infection, immunocompromised patients, or frontal or sphenoidal sinusitis 3, 6

If symptoms fail to improve after 72 hours or worsen at any time, reassess the patient and switch antibiotics, with options including switching to respiratory fluoroquinolone, high-dose amoxicillin-clavulanate, or ceftriaxone 1 g IM/IV daily for 5 days 3, 4
After 7 days without improvement, reevaluate for misdiagnosis, complications, need for imaging or endoscopy, or sinus aspiration for culture 1, 2, 3, 4

Avoid prescribing fluoroquinolones as first-line therapy for uncomplicated cases to prevent promoting resistance, and reserve these for treatment failures or true penicillin allergy 1, 4
Recognize that watchful waiting without antibiotics is appropriate for uncomplicated cases with assured follow-up, reducing adverse events and antibiotic resistance 1, 2, 7