What is the recommended high dose amoxicillin (amoxicillin) dosage for treating bacterial infections?

High-Dose Amoxicillin Dosing for Bacterial Infections

The recommended high-dose amoxicillin dosage for adults is 875 mg twice daily or 500 mg three times daily for mild to moderate infections, and 875 mg twice daily or 500 mg every 8 hours for severe infections. 1

Adult Dosing Guidelines

Standard vs. High-Dose Regimens

• Standard dose: 750-1750 mg/day in divided doses every 8-12 hours 1
• High dose:
  • 875 mg twice daily (1750 mg/day) 1
  • 500 mg three times daily (1500 mg/day) 1
  • For severe infections requiring maximum coverage: up to 4 g/day 2

Indications for High-Dose Therapy

High-dose amoxicillin should be considered in the following situations:

1. Geographic factors:

   • Areas with high prevalence (>10%) of penicillin-resistant Streptococcus pneumoniae 2

2. Patient factors:

   • Recent antibiotic use (within 4-6 weeks) 2
   • Age >65 years 2
   • Immunocompromised status 2
   • Moderate to severe infection 2
   • History of recurrent infections 2

3. Disease severity:

   • Evidence of systemic toxicity with temperature ≥39°C (102°F) 2
   • Risk of suppurative complications 2
   • Frontal or sphenoidal sinusitis 2

Pediatric Dosing Guidelines

Standard vs. High-Dose Regimens

• Standard dose: 20-45 mg/kg/day in divided doses every 8-12 hours 1
• High dose:
  • 45 mg/kg/day in divided doses every 12 hours 1
  • 40 mg/kg/day in divided doses every 8 hours 1
  • For maximum coverage: up to 90 mg/kg/day 2

Special Considerations for Pediatric Patients

• For children <12 weeks: maximum dose is 30 mg/kg/day divided every 12 hours 1
• For children at high risk of resistant infections: 80-90 mg/kg/day 2
• For children in daycare settings: consider high-dose regimen 2

Duration of Therapy

• Most bacterial infections: 7-10 days 1
• Streptococcus pyogenes infections: minimum 10 days to prevent acute rheumatic fever 1
• Treatment should continue for 48-72 hours beyond symptom resolution 1

Administration Considerations

• Take at the start of a meal to minimize gastrointestinal intolerance 1
• For oral suspension, shake well before using 1

Renal Dosing Adjustments

• GFR 10-30 mL/min: 500 mg or 250 mg every 12 hours 1
• GFR <10 mL/min: 500 mg or 250 mg every 24 hours 1
• Patients with severe renal impairment (GFR <30 mL/min) should NOT receive the 875 mg dose 1

Common Pitfalls and Caveats

• High-dose amoxicillin alone may not be sufficient for infections with high risk of β-lactamase-producing organisms (e.g., H. influenzae, M. catarrhalis) - consider amoxicillin-clavulanate instead 2
• Despite theoretical benefits, a randomized clinical trial found no significant difference between high-dose and standard-dose amoxicillin-clavulanate for acute sinusitis 3
• Repeated high-dose amoxicillin can increase resistant oral flora, which may persist for 4-7 weeks 4
• For penicillin-allergic patients, alternative agents should be considered based on the type of allergy and suspected pathogens 2

Remember that the decision to use high-dose amoxicillin should be based on the severity of infection, risk factors for resistant organisms, and local antimicrobial resistance patterns to optimize treatment outcomes while minimizing the development of resistance.