Dosing of Amoxicillin-Clavulanate for E. faecalis UTI with Severe Renal Impairment
For a patient with E. faecalis UTI and creatinine clearance of 20.48 mL/min, the recommended dose of amoxicillin-clavulanate is 500 mg every 12 hours.
Rationale for Dosing
Amoxicillin-clavulanate is an appropriate choice for treating E. faecalis UTIs, but requires dose adjustment in patients with renal impairment:
- The FDA label clearly states that patients with renal impairment with a glomerular filtration rate of <30 mL/min should not receive the 875 mg dose 1
- With a creatinine clearance of 20.48 mL/min, this patient has severe renal impairment requiring dose adjustment
- Standard dosing would typically be 875 mg every 12 hours for severe infections, but this must be reduced in renal impairment 1
Treatment Considerations for E. faecalis UTI
E. faecalis is generally susceptible to amoxicillin-clavulanate, making it an appropriate choice:
- E. faecalis has shown high susceptibility rates to amoxicillin-clavulanate (91.84% susceptible) in clinical studies 2
- Amoxicillin-clavulanate has demonstrated efficacy against amoxicillin-resistant organisms in urinary tract infections with success rates of about 70% 3
- For UTIs specifically, amoxicillin-clavulanate at appropriate doses can achieve adequate urinary concentrations even with reduced dosing 4
Renal Adjustment Protocol
The dosing adjustment for amoxicillin-clavulanate in renal impairment follows these principles:
- Patients with creatinine clearance between 10-30 mL/min should receive reduced dosing
- The 500 mg formulation should be used instead of the 875 mg formulation
- Dosing interval remains at every 12 hours to maintain adequate drug levels
Duration of Therapy
For E. faecalis UTI, the recommended duration of therapy depends on infection severity:
- For uncomplicated UTI: 5-7 days of therapy 4
- For complicated UTI: 10-14 days of therapy 4
- For severe pyelonephritis: 14 days of therapy 4
Monitoring Recommendations
Due to the patient's renal impairment, close monitoring is essential:
- Assess clinical response within 48-72 hours of starting treatment 4
- Monitor renal function regularly during treatment
- Evaluate for signs of treatment failure that might indicate need for alternative therapy
- Consider follow-up urine culture if symptoms persist beyond 72 hours
Alternative Options
If the patient does not respond to amoxicillin-clavulanate or develops intolerance:
- Nitrofurantoin may be considered for uncomplicated lower UTI, but is contraindicated in severe renal impairment (CrCl <30 mL/min) 4
- Fosfomycin 3g single dose may be an option for uncomplicated lower UTI 4, 5
- For complicated UTI requiring parenteral therapy, options include ampicillin (with dose adjustment) or vancomycin (with careful monitoring) 4
Important Cautions
- Administer amoxicillin-clavulanate at the start of a meal to minimize gastrointestinal intolerance 1
- Avoid nitrofurantoin in this patient due to severe renal impairment
- Monitor for signs of drug accumulation due to reduced renal clearance
- Consider therapeutic drug monitoring if available, especially if treatment response is suboptimal
This dosing recommendation balances the need for effective antimicrobial therapy against E. faecalis while accounting for the patient's significantly reduced renal function to minimize toxicity risks.