What is the recommended antibiotic (abx) and dose for a patient with a tooth abscess?

Antibiotic Treatment for Tooth Abscess

Surgical drainage through incision and drainage, extraction, or root canal therapy is the primary treatment for tooth abscesses, and antibiotics should only be added when there is systemic involvement (fever, malaise, tachycardia) or spreading infection (cellulitis, diffuse swelling), not for localized abscesses alone. 1

Primary Treatment Approach

• Surgical intervention is mandatory and should never be delayed - this includes root canal therapy, tooth extraction, or incision and drainage depending on the clinical situation 1
• Antibiotics without surgical drainage are ineffective and should not be used as monotherapy 1
• Multiple systematic reviews demonstrate no significant difference in pain or swelling outcomes when antibiotics are added to adequate surgical treatment for localized abscesses 1

When to Add Antibiotics

Add antibiotics ONLY when any of the following are present:

• Systemic signs: fever, malaise, tachycardia, tachypnea, or elevated white blood cell count 1
• Spreading infection: cellulitis, diffuse swelling extending beyond the localized area, or lymph node involvement 1
• Immunocompromised patients: including those with diabetes, HIV, or on immunosuppressive medications 1
• Inadequate surgical access: when complete drainage cannot be achieved 1

First-Line Antibiotic Regimen (When Indicated)

Amoxicillin or Penicillin VK for 5-7 days:

• Adults: Amoxicillin 500 mg every 8 hours OR 875 mg every 12 hours 2
• Pediatric (≥3 months and <40 kg): Amoxicillin 25-50 mg/kg/day divided every 8-12 hours 1, 2
• Duration: 5 days is typically sufficient; maximum 7 days with adequate source control 1

Second-Line Options

For penicillin-allergic patients:

• Clindamycin (preferred alternative) 1, 3
  • Adults: 300-450 mg orally three times daily 1, 3
  • Pediatric: 10-20 mg/kg/day divided into 3 doses (maximum 40 mg/kg/day) 1, 3
  • Caution: Higher risk of Clostridioides difficile infection; discontinue if significant diarrhea develops 3

For treatment failures or moderate-to-severe infections:

• Amoxicillin-clavulanate (provides beta-lactamase coverage and enhanced anaerobic activity) 1
  • Adults: 875/125 mg twice daily 4, 1
  • Pediatric: 90 mg/kg/day (of amoxicillin component) divided twice daily 1

Alternative combination for failures:

• Amoxicillin PLUS metronidazole (covers resistant anaerobes) 1

Severe Infections Requiring IV Therapy

For patients with systemic toxicity, deep tissue involvement, or inability to take oral medications:

• Clindamycin: 600-900 mg IV every 6-8 hours (adults); 10-13 mg/kg/dose IV every 6-8 hours (pediatric) 1
• Piperacillin-tazobactam: 3.375 g IV every 6 hours or 4.5 g IV every 8 hours (for broader gram-negative coverage) 1
• Ceftriaxone 1 g IV every 24 hours PLUS metronidazole 500 mg IV every 8 hours (alternative broad-spectrum regimen) 1
• Transition to oral therapy once clinically improved 1

Special Considerations and Pitfalls

• Do NOT use fluoroquinolones - they provide inadequate coverage for typical dental abscess pathogens 1
• MRSA coverage is NOT routinely needed for dental abscesses in immunocompetent patients 1
• Penicillin remains highly effective clinically despite moderate in vitro susceptibility results, particularly when combined with adequate surgical drainage 5
• Most dental abscesses are polymicrobial (98%), involving both aerobic streptococci (especially Viridans group) and anaerobes (especially Prevotella species) 5
• Renal dosing adjustments: Patients with GFR <30 mL/min should NOT receive amoxicillin 875 mg dose; use 500 mg every 12 hours instead 2
• For GFR <10 mL/min or hemodialysis: amoxicillin 500 mg every 24 hours with additional dose after dialysis 2

Treatment Algorithm Summary

1. Assess for systemic involvement or spreading infection (fever, cellulitis, lymphadenopathy, immunocompromise)
2. Perform surgical drainage immediately (extraction, incision and drainage, or root canal)
3. If localized abscess without systemic signs: surgery alone is sufficient 1
4. If systemic signs or spreading infection present: add amoxicillin 500 mg TID or 875 mg BID for 5-7 days 1, 2
5. If penicillin-allergic: use clindamycin 300-450 mg TID 1, 3
6. If treatment failure after 48-72 hours: switch to amoxicillin-clavulanate or add metronidazole 1