For an adult with no penicillin allergy and normal renal and hepatic function, what is the appropriate amoxicillin dosage and duration for a bacterial tooth infection?

Amoxicillin for Toothache: Dosing and Duration Guidelines

For an adult with bacterial tooth infection and no penicillin allergy, prescribe amoxicillin 500 mg every 8 hours (or 875 mg every 12 hours) for 5-7 days, but only after or concurrent with definitive surgical treatment (drainage, root canal, or extraction), as antibiotics alone without source control are insufficient. 1

Critical First Principle: Surgery Before Antibiotics

• Surgical intervention (incision and drainage, root canal therapy, or tooth extraction) is the cornerstone of treatment and should not be delayed. 1
• Multiple systematic reviews demonstrate no statistically significant improvement in pain or swelling when antibiotics are added to surgical treatment alone. 1
• Antibiotics without surgical drainage provide minimal benefit, as the source of infection must be physically removed. 1

When Antibiotics Are Actually Indicated

Add antibiotics to surgical treatment only when:

• Systemic involvement is present: fever, tachycardia, tachypnea, or elevated white blood cell count 1
• Evidence of spreading infection: cellulitis, diffuse swelling beyond the localized abscess 1
• Patient is immunocompromised or medically compromised 1
• Infection is progressing despite adequate drainage 1

Amoxicillin Dosing Regimen

Standard adult dosing:

• Amoxicillin 500 mg orally every 8 hours (three times daily) for 5-7 days 1
• Alternative: Amoxicillin 875 mg orally every 12 hours (twice daily) for 5-7 days 1

Pediatric dosing:

• 25-50 mg/kg/day divided into 3-4 doses 1

When to Upgrade from Amoxicillin to Amoxicillin-Clavulanate

Consider amoxicillin-clavulanate (Augmentin) instead of amoxicillin alone if:

• Moderate to severe symptoms are present 1
• Patient has used antibiotics within the past month 1
• Previous treatment failure with amoxicillin 1
• Rapidly spreading cellulitis 1
• Patient is immunocompromised 1
• Significant comorbidities present 1
• Patient age >65 years 1
• Geographic regions with high rates of penicillin-resistant organisms 1

Amoxicillin-clavulanate dosing:

• 875 mg/125 mg orally twice daily for 5-7 days 1
• This provides enhanced anaerobic coverage and protection against beta-lactamase producing organisms 1

Alternative for Penicillin Allergy

If the patient has a penicillin allergy:

• Clindamycin 300-450 mg orally three times daily for 5-7 days 1, 2
• Clindamycin provides excellent coverage against all odontogenic pathogens 3
• Caution: Higher risk of Clostridioides difficile infection with clindamycin 1

Treatment Failures: Second-Line Options

If no improvement after 48-72 hours of amoxicillin:

• Switch to amoxicillin-clavulanate 875/125 mg twice daily 1
• Or add metronidazole to amoxicillin (but never metronidazole alone) 1
• Consider clindamycin 300-450 mg three times daily 1

Maximum Treatment Duration

• Do not exceed 7 days of antibiotic treatment in most cases with adequate source control 1
• Prolonged antibiotic courses without surgical intervention are inappropriate and promote resistance 1

Common Pitfalls to Avoid

Do not prescribe antibiotics for:

• Irreversible pulpitis (toothache without abscess) - this requires only dental treatment, not antibiotics 4
• Localized abscess without systemic symptoms - drainage alone is sufficient 1
• Chronic dental infections - these require definitive dental treatment, not prolonged antibiotics 4

Critical errors:

• Prescribing antibiotics without arranging definitive dental treatment creates false reassurance and delays appropriate care 1
• Using antibiotics as a substitute for surgical drainage leads to treatment failure 1
• Overprescribing antibiotics for non-indicated conditions (like simple pulpitis) contributes to antibiotic resistance 4

Renal Dosing Adjustments

For patients with renal impairment:

• Creatinine clearance 10-30 mL/min: Amoxicillin-clavulanate 875/125 mg once daily (or 500/125 mg every 12 hours) 1
• Creatinine clearance <10 mL/min: Amoxicillin-clavulanate 875/125 mg once daily 1
• Hemodialysis patients: Administer dose after each dialysis session 1

Evidence Quality Note

The recommendation prioritizes recent high-quality guidelines from the American Dental Association and Infectious Diseases Society of America over older sinusitis guidelines 5, as dental abscess management differs fundamentally from upper respiratory infections. The 2018 Cope study provides the strongest evidence that antibiotics add minimal benefit to surgical treatment for localized dental abscesses. 1