Recommended Antibiotics for Bacterial Sinus Infections
Amoxicillin 500 mg twice daily for 10-14 days is the first-line antibiotic for most adults with acute bacterial sinusitis. 1, 2
First-Line Treatment Algorithm
Standard-dose amoxicillin is the preferred initial choice for uncomplicated acute bacterial sinusitis in adults and children 1, 2:
- Adults: 500 mg twice daily (mild disease) or 875 mg twice daily (moderate disease) for 10-14 days 1
- Children: 45 mg/kg/day divided into 2 doses 1, 2
High-dose amoxicillin or amoxicillin-clavulanate should be used in high-risk situations 1, 2:
- Communities with high prevalence of drug-resistant S. pneumoniae (>10% resistance) 2
- Children <2 years old 1
- Daycare attendance 1, 2
- Recent antibiotic use within 4-6 weeks 1, 2
- High-dose regimen: Amoxicillin 80-90 mg/kg/day (children) or 875 mg twice daily (adults) 1
Penicillin-Allergic Patients
For documented penicillin allergy, second- or third-generation cephalosporins are the preferred alternatives 1, 2:
- Cefuroxime-axetil (second-generation) 1
- Cefpodoxime-proxetil (third-generation, superior activity against H. influenzae) 1
- Cefdinir (third-generation) 1, 2
The risk of cross-reactivity between penicillins and second/third-generation cephalosporins is negligible 1. For severe Type I hypersensitivity (anaphylaxis), reserve levofloxacin 500 mg once daily for 10-14 days 1, 3.
Second-Line Treatment for Treatment Failure
If no improvement occurs after 3-5 days of initial therapy, switch antibiotics 1:
High-dose amoxicillin-clavulanate (875 mg/125 mg twice daily for adults; 90 mg/kg/day amoxicillin component for children) provides coverage against β-lactamase-producing H. influenzae and M. catarrhalis 1, 2.
Respiratory fluoroquinolones are reserved for second-line therapy 1, 3:
- Levofloxacin 500 mg once daily for 10-14 days (or 750 mg once daily for 5 days) 1, 3
- Moxifloxacin 400 mg once daily for 10 days 1
- These provide 90-92% predicted clinical efficacy against drug-resistant S. pneumoniae and β-lactamase-producing organisms 1, 3
Treatment Duration
Standard duration is 10-14 days or until symptom-free for 7 days 1, 2. Some cephalosporins and fluoroquinolones are effective in 5-day courses 1, 3, 4. Shorter 5-7 day courses have comparable efficacy with fewer side effects for uncomplicated maxillary sinusitis 1, 4.
Antibiotics to AVOID
Azithromycin and other macrolides should NOT be used due to resistance rates of 20-25% for S. pneumoniae and H. influenzae 1. Trimethoprim-sulfamethoxazole has resistance rates exceeding 50% for S. pneumoniae and should be avoided 1. Doxycycline has a 20-25% predicted bacteriologic failure rate and limited activity against H. influenzae 1.
Adjunctive Therapies
Intranasal corticosteroids (mometasone, fluticasone, budesonide) twice daily are strongly recommended as adjuncts to antibiotic therapy 1. Short-term oral corticosteroids may be considered for marked mucosal edema or severe pain unresponsive to initial treatment 1.
Critical Pitfalls to Avoid
Reassess patients at 72 hours (children) or 3-5 days (adults) if no improvement occurs 1. Do not continue ineffective therapy beyond this timepoint 1. Complete the full antibiotic course even after symptoms improve to prevent relapse 1. Reserve fluoroquinolones for treatment failures or severe disease to prevent resistance development 1, 3.