What is the recommended dose of amoxicillin (amox) for an adult patient with infected gums and no known allergies to penicillin or significant renal impairment?

Amoxicillin Dosing for Infected Gums (Odontogenic Infections)

For adults with infected gums (odontogenic infections), amoxicillin 500 mg every 8 hours for 3-7 days is the recommended first-line treatment, always combined with definitive dental intervention such as drainage, debridement, or tooth extraction. 1, 2

First-Line Antibiotic Regimen

• Amoxicillin 500 mg orally every 8 hours is the standard dose for odontogenic infections originating from dental pulp or periodontal structures 1
• Treatment duration should be 3-7 days, with emerging evidence supporting shorter courses (3-5 days) as equally effective as traditional 7-day regimens 2
• Antibiotics must always be combined with definitive dental treatment including drainage of abscesses, root canal debridement, or tooth extraction—antibiotics alone are insufficient 1

When to Escalate Therapy

• If no clinical improvement occurs within 2-3 days, escalate to second-line regimens 1:
  • Amoxicillin-clavulanate 875/125 mg twice daily for better coverage of beta-lactamase-producing organisms 3, 1
  • High-dose amoxicillin-clavulanate 2000/125 mg twice daily if risk factors for resistant organisms are present (recent antibiotic use within 4-6 weeks, age >65, immunocompromised status) 3
  • Alternative: Amoxicillin 500 mg plus metronidazole 500 mg, both every 8 hours for enhanced anaerobic coverage 1, 4

Penicillin Allergy Alternatives

• For patients with penicillin allergy, use clindamycin 600 mg orally every 8 hours as the preferred alternative 5, 1
• Macrolides should be avoided due to high resistance rates (>40% against common oral pathogens) 5, 1

Critical Clinical Caveats

• Odontogenic infections (acute dentoalveolar abscess) are most commonly caused by gram-positive anaerobic or facultative bacteria, making penicillins highly effective 1
• Periodontal infections may require different antibiotic strategies—the combination of amoxicillin plus metronidazole shows superior clinical and microbiological outcomes for periodontitis, particularly in patients positive for Porphyromonas gingivalis 4
• Prophylactic dosing (2000 mg single dose 1 hour before dental procedures) is reserved for high-risk patients such as those on hemodialysis or with cardiac conditions requiring endocarditis prophylaxis 5
• Renal impairment requires dose adjustment only in severe cases (GFR <30 mL/min)—consult nephrology for specific modifications 5, 6

Common Pitfalls to Avoid

• Never prescribe antibiotics without definitive dental intervention—this leads to treatment failure and promotes resistance 1
• Avoid prolonged courses beyond 7 days unless there is documented lack of response with appropriate dental treatment 2
• Do not use amoxicillin-clavulanate as first-line unless there are specific risk factors for resistant organisms, as standard amoxicillin is equally effective for most odontogenic infections and has fewer gastrointestinal side effects 1, 7