Oral Amoxicillin Dosing for Susceptible Enterococcus faecalis Infections

Standard Oral Dosing Regimen

• The American College of Cardiology recommends amoxicillin 500 mg orally three times daily for uncomplicated E. faecalis infections in adults, including genitourinary and skin/soft tissue infections 1

Duration of Therapy

• The minimum treatment duration is 7 days for uncomplicated infections such as urogenital sources 1
• Oral amoxicillin can serve as step-down therapy after clinical improvement for more serious infections requiring initial IV therapy 1

Important Clinical Considerations

• The Infectious Diseases Society of America recommends confirm susceptibility testing before relying on oral therapy for serious infections 1
• Endocarditis requires IV combination therapy and cannot be treated with oral amoxicillin alone 2

Pediatric Dosing Considerations

• The American Academy of Pediatrics recommends ampicillin 200-300 mg/kg/day divided every 4-6 hours (up to 12 g daily) for serious pediatric infections, which can inform oral step-down dosing proportionally 2, 4

Common Pitfalls to Avoid

• The Centers for Disease Control and Prevention advises against underdosing, as the full 500 mg three times daily (1500 mg total daily) is necessary for adequate tissue penetration 1
• The Society for Healthcare Epidemiology of America recommends not using amoxicillin for vancomycin-resistant strains, as these require linezolid 600 mg PO every 12 hours instead 1
• The Infectious Diseases Society of America warns against assuming all enterococci are E. faecalis, as E. faecium has different resistance patterns and may not respond to amoxicillin 4