Amoxicillin Dosing for Toothache in Adults
For an adult with a toothache requiring antibiotic therapy, prescribe amoxicillin 500 mg orally three times daily for 5-7 days. 1
Critical First Step: Determine if Antibiotics Are Actually Needed
Before prescribing any antibiotic, you must distinguish between conditions that require antibiotics versus those that need only surgical intervention:
Simple toothache without infection does NOT benefit from antibiotics - research demonstrates that penicillin provides no benefit for undifferentiated dental pain without overt infection, with infection rates identical between antibiotic and placebo groups (9% vs 10%, p=0.90). 2
Acute dental abscesses require surgical drainage first - antibiotics alone are insufficient and should only follow incision and drainage. 1
Irreversible pulpitis does not respond to antibiotics - this requires dental intervention, not antimicrobial therapy. 1
When Antibiotics ARE Indicated
Prescribe antibiotics when systemic signs of infection are present:
- Fever 1
- Lymphadenopathy 1
- Cellulitis or diffuse swelling 1
- Infection extending to underlying soft tissues 1
- Acute dentoalveolar abscess (after drainage) 1
Standard Dosing Regimen
The recommended dose is amoxicillin 500 mg orally three times daily (every 8 hours) for 5-7 days. 1, 3
Alternative dosing from FDA labeling for severe infections: 875 mg every 12 hours or 500 mg every 8 hours. 3
When to Upgrade to Amoxicillin-Clavulanate
For more complex infections or suspected beta-lactamase producing organisms:
- Amoxicillin-clavulanate 875/125 mg twice daily is the preferred regimen 1
- This combination showed 88.2% clinical success rates in odontogenic infections, comparable to clindamycin (89.7%), with faster improvement by day 5 4
- Research demonstrates significantly better pain control and reduced swelling with amoxicillin-clavulanate compared to amoxicillin alone after oral surgical procedures 5
Penicillin Allergy Alternative
For patients with penicillin allergy, prescribe clindamycin 300-400 mg three times daily. 1
Duration of Therapy
- 5-7 days is the standard duration for dental infections 1
- One randomized trial found 3 days of amoxicillin non-inferior to 7 days for odontogenic infections requiring extraction, though this study had patients starting antibiotics 2 days pre-extraction (not typical practice) 6
- Continue treatment for minimum 48-72 hours beyond resolution of symptoms 3
Administration Instructions
Take amoxicillin at the start of meals to minimize gastrointestinal intolerance. 3
Common Pitfalls to Avoid
- Do not prescribe antibiotics for simple toothache without signs of infection - this promotes antibiotic resistance without clinical benefit 2
- Do not rely on antibiotics alone for abscesses - surgical drainage must be performed first 1
- Do not delay necessary dental intervention while treating with antibiotics - definitive treatment requires addressing the source 1
- Do not use first-generation cephalosporins (cephalexin, cefadroxil) - they have inadequate coverage for H. influenzae 7
Adverse Effects to Counsel Patients About
Antibiotics increase risk of mild, transient adverse effects (RR 1.98) - meaning 1 in 21 patients will experience side effects such as diarrhea, raised liver enzymes, or headache. 4, 8
Renal Dosing Adjustments
For patients with severe renal impairment (GFR <30 mL/min): reduce to 500 mg or 250 mg every 12-24 hours depending on severity. 3