Amoxicillin Dosing for Sinusitis, Otitis, and Dental Infections
For adults with mild sinusitis or otitis who have not received antibiotics in the past 4-6 weeks, use amoxicillin 1.5-4 g/day (typically 500 mg three times daily or 875 mg twice daily) for 10-14 days. 1, 2
Adult Dosing Recommendations
Mild Disease (No Recent Antibiotic Use)
- Standard dose: Amoxicillin 500 mg twice daily for 10-14 days is the typical regimen 2
- Alternative dosing: 1.5-4 g/day divided into 2-3 doses is acceptable 1
- This applies to patients who have NOT received antibiotics in the previous 4-6 weeks 1
Moderate Disease or Recent Antibiotic Use
- High-dose amoxicillin/clavulanate: 4 g amoxicillin/250 mg clavulanate per day (typically 875 mg/125 mg twice daily) 1
- Use this regimen if the patient has received antibiotics in the past 4-6 weeks 1
- Also indicated for areas with high prevalence of penicillin-resistant S. pneumoniae 1, 2
When to Use Amoxicillin-Clavulanate Instead of Plain Amoxicillin
- Recent antibiotic use (within 4-6 weeks) 2
- Moderate to severe illness 2
- Treatment failure with amoxicillin 2
- High prevalence of β-lactamase-producing H. influenzae 2
- Possible dental infection (where anaerobes are more likely) 3
Pediatric Dosing
Children with Mild Disease
- High-dose amoxicillin: 90 mg/kg/day divided into 2 doses 1
- High-dose amoxicillin/clavulanate: 90 mg/6.4 mg per kg per day in 2 divided doses (maximum 2g per dose) 1, 4
- Use high-dose formulations for children <2 years, those in daycare, or with recent antibiotic exposure 4
Treatment Duration and Monitoring
- Standard duration: 10-14 days for both sinusitis and otitis 2
- Alternative approach: Continue until symptom-free for 7 days 2
- Reassess at 72 hours: If no improvement or worsening, switch antibiotics or reevaluate diagnosis 1, 2
Penicillin Allergy Alternatives
For patients with β-lactam allergies, consider: 1
- TMP/SMX
- Doxycycline
- Azithromycin or clarithromycin
- Important caveat: These alternatives have bacteriologic failure rates of 20-25% 1
Dental Infections
- Amoxicillin is effective for dental-origin sinusitis, which often involves anaerobic bacteria 3
- Consider amoxicillin/clavulanate for better anaerobic coverage in suspected dental infections 3
- Dosing follows the same principles as sinusitis treatment 3
Critical Pitfalls to Avoid
- Do not treat viral infections with antibiotics - this contributes to resistance and provides no benefit 2
- Do not underdose in high-resistance areas - standard-dose amoxicillin may fail where resistant S. pneumoniae is prevalent 1, 2
- Do not use standard-dose amoxicillin alone for preseptal cellulitis - inadequate coverage against beta-lactamase producers 4
- Complete the full course - incomplete treatment leads to relapse and resistance 2
Clinical Efficacy Data
The predicted clinical efficacy for amoxicillin regimens in adults: 1
- High-dose amoxicillin/clavulanate (4 g/250 mg/day): 90-92%
- Standard amoxicillin/clavulanate (1.75 g/250 mg/day): 90-92%
- High-dose amoxicillin (4 g/day): 83-88%
- Standard amoxicillin (1.5 g/day): 83-88%
- Spontaneous resolution rate without treatment: 62% 1