What is the recommended dosing of amoxicillin (amoxicillin) for an adult patient with a possible abscessed wisdom tooth and no known allergies or impaired renal function (Impaired renal function)?

Amoxicillin Dosing for Suspected Abscessed Wisdom Tooth in Adults

For an adult with a suspected abscessed wisdom tooth, prescribe amoxicillin 500 mg three times daily for 5 days, but only if systemic symptoms (fever, malaise, tachycardia) or spreading infection (cellulitis, diffuse swelling) are present—otherwise, surgical drainage alone is sufficient. 1

Primary Treatment Principle

• Surgical intervention is the cornerstone of treatment and should not be delayed 1
• Antibiotics are adjunctive therapy only and should never replace definitive surgical management (extraction or incision and drainage) 1
• Multiple systematic reviews demonstrate no statistically significant differences in pain or swelling outcomes when antibiotics are added to surgical treatment in the absence of systemic involvement 1

When to Add Antibiotics

Prescribe antibiotics only when:

• Systemic symptoms are present: fever, tachycardia, tachypnea, 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
• Progressive infection requiring referral to oral surgeon 1

First-Line Antibiotic Dosing

Amoxicillin dosing options for adults:

• 500 mg orally every 8 hours (three times daily) 2
• Alternative: 875 mg orally every 12 hours (twice daily) for more severe infections 2
• Duration: 5 days minimum 1, 3
• Take at the start of meals to minimize gastrointestinal intolerance 2

The evidence supports both phenoxymethylpenicillin and amoxicillin as first-choice agents 1, but amoxicillin is preferred in practice due to better oral absorption and less frequent dosing requirements.

Treatment Duration

• Standard duration: 5 days 1
• Maximum duration: 7 days with adequate source control 1
• Continue therapy for minimum 48-72 hours beyond resolution of symptoms 2

Second-Line Options (Treatment Failures or Penicillin Allergy)

If no improvement within 2-3 days on amoxicillin:

• Amoxicillin-clavulanate 875/125 mg orally twice daily 1, 4
• This provides enhanced coverage against beta-lactamase producing organisms 1

For penicillin-allergic patients:

• Clindamycin 300-450 mg orally three times daily 1
• Clindamycin is preferred over macrolides for dental infections 3

Evidence Quality and Nuances

The recommendation for amoxicillin 500 mg three times daily comes from established dental practice guidelines 1, 3, though the FDA label also supports 875 mg twice daily for more severe infections 2. A randomized trial of 472 patients demonstrated that amoxicillin-clavulanate 875/125 mg twice daily achieved 88.2% clinical success in odontogenic infections 4, supporting the efficacy of this dosing range.

Critical caveat: The evidence base for antibiotic use in dental abscesses comes primarily from studies of third molar extractions in healthy patients 5. The 2018 Cope study found no significant differences in pain or swelling when comparing penicillin versus placebo when both groups received surgical intervention 1. This underscores that antibiotics should not be prescribed routinely without systemic involvement.

Common Pitfalls to Avoid

• Do not prescribe antibiotics without surgical drainage—this delays definitive treatment and promotes antibiotic resistance 1
• Do not use fluoroquinolones—they provide inadequate coverage for typical dental abscess pathogens 1
• Do not exceed 7 days of antibiotic therapy in patients with adequate source control 1
• Do not prescribe antibiotics for localized abscesses without systemic symptoms—the number needed to treat is 12 patients to prevent one infection, raising concerns about antibiotic resistance 5

Renal Impairment Considerations

For patients with severe renal impairment (though you specified normal renal function):

• GFR 10-30 mL/min: 500 mg or 250 mg every 12 hours 2
• GFR <10 mL/min: 500 mg or 250 mg every 24 hours 2
• Do NOT use the 875 mg dose if GFR <30 mL/min 2