Amoxicillin Dosage for Mouth Infection in Adults
For adult mouth infections, prescribe amoxicillin 500 mg three times daily for 7-10 days, or alternatively amoxicillin-clavulanate 875/125 mg twice daily for the same duration if broader coverage is needed.
Standard Dosing Regimens
Amoxicillin Monotherapy
- Amoxicillin 500 mg three times daily (every 8 hours) is the standard dose for mild-to-moderate dental and oral infections 1, 2
- The FDA-approved adult dosing range is 750-1750 mg/day in divided doses every 8-12 hours 2
- Treatment duration should be 7-10 days to ensure adequate bacterial eradication and prevent treatment failure 1, 3
Amoxicillin-Clavulanate (Augmentin) for Enhanced Coverage
- Amoxicillin-clavulanate 875/125 mg twice daily is preferred when beta-lactamase-producing organisms are suspected or when broader coverage is clinically indicated 1, 4, 5
- Alternative regimen: 500/125 mg three times daily provides equivalent efficacy with potentially more gastrointestinal side effects 1, 4
- The twice-daily 875/125 mg formulation has significantly less severe diarrhea (1% vs 2%) compared to three-times-daily dosing 1
Clinical Decision Algorithm
When to Use Amoxicillin Alone
- Uncomplicated dental infections (periapical abscess, post-extraction infection) in patients without recent antibiotic exposure 1, 3
- Odontogenic infections requiring tooth extraction 3
- Patients with no risk factors for resistant organisms 1
When to Use Amoxicillin-Clavulanate
- Oral surgical interventions (impacted wisdom teeth removal, apicoectomy, complicated extractions) 6
- Odontogenic abscesses where anaerobic coverage is beneficial 6
- Recent antibiotic use within 4-6 weeks (risk factor for resistant organisms) 7, 1
- Moderate-to-severe infections or when initial therapy fails 1
Treatment Duration Evidence
Standard Duration: 7-10 Days
- Most dental infections require 7-10 days of therapy to prevent treatment failure and resistance development 1, 3
- One RCT comparing 3-day vs 7-day amoxicillin courses for odontogenic infections showed no significant difference, but this study had patients starting antibiotics 2 days before extraction (not standard practice) 3
- Five-day courses are only appropriate for specific high-dose respiratory infection regimens, not standard dental infections 1
Post-Surgical Prophylaxis
- For oral-surgical interventions, amoxicillin-clavulanate 625 mg three times daily for 5-10 days post-operatively demonstrated superior pain and swelling control compared to amoxicillin alone 6
Important Clinical Considerations
Dosing Pitfalls to Avoid
- Never substitute two 250 mg tablets for one 500 mg tablet of amoxicillin-clavulanate, as this results in excessive clavulanate dosing and increased gastrointestinal side effects 1
- Ensure patients complete the full course even if symptoms improve to prevent treatment failure and resistance 1
Patient-Specific Factors
- Renal impairment: Reduce dose when GFR <30 mL/min 2
- Penicillin allergy: Absolute contraindication if history of anaphylaxis or Stevens-Johnson syndrome 2
- Food intake has no effect on amoxicillin absorption 8
Monitoring Parameters
- Assess clinical response at 48 hours: pain reduction, decreased swelling, improved function 6
- Re-evaluate at 7 days to confirm resolution 6
- If no improvement or worsening after 72 hours, consider switching to broader-spectrum therapy or surgical intervention 7, 1
Adverse Effects
- Most common: diarrhea, rash, vomiting, nausea (>1% incidence) 2
- Amoxicillin-clavulanate has higher gastrointestinal side effect rates, particularly with three-times-daily dosing 1, 4
- Monitor for Clostridioides difficile-associated diarrhea if severe diarrhea develops 2