Ciprofloxacin and Amoxicillin-Clavulanate Dosing for eGFR 47 mL/min
For a patient with an eGFR of 47 mL/min (moderate renal impairment, CrCl 30-50 mL/min), ciprofloxacin should be dosed at 250-500 mg every 12 hours, and amoxicillin-clavulanate (Clavulin) can be given at standard doses without adjustment.
Ciprofloxacin Dosing
Recommended Dose Adjustment
- The FDA-approved dosing for ciprofloxacin in patients with CrCl 30-50 mL/min is 250-500 mg every 12 hours 1
- This represents a dose reduction from the standard 500-750 mg every 12 hours used in patients with normal renal function 1
- The specific dose within this range (250 mg vs 500 mg) should be selected based on infection severity and pathogen susceptibility 1
Pharmacokinetic Rationale
- In patients with impaired renal function (CrCl <50 mL/min), the area under the curve doubles, renal clearance is reduced to one-fourth, and elimination half-life is prolonged by approximately 1.7-fold compared to normal renal function 2
- Ciprofloxacin is primarily eliminated renally (approximately 67% of total clearance), but alternative pathways through biliary and intestinal routes partially compensate for reduced renal excretion 1, 3
- A 50% dose reduction is appropriate when creatinine clearance falls below 50 mL/min to achieve serum concentrations similar to those in patients with normal renal function 2
Clinical Considerations for Dose Selection
- For infections caused by highly susceptible pathogens (MIC ≤0.125 mg/L), 400 mg every 12 hours achieves adequate PK/PD targets (AUC/MIC >125) in patients with eGFR <130 mL/min 4
- However, for less susceptible pathogens (MIC ≥0.25 mg/L), standard reduced doses may not achieve adequate target attainment 5
- The guideline recommendation of 250-500 mg every 12 hours for CrCl 30-50 mL/min should be applied, with 500 mg preferred for more resistant organisms 6, 1
Amoxicillin-Clavulanate (Clavulin) Dosing
Recommended Dose
- Standard dosing regimens can be used for patients with CrCl >30 mL/min without adjustment 7
- With an eGFR of 47 mL/min, this patient does not require dose reduction of amoxicillin-clavulanate 7
- Typical adult dosing would be 875 mg/125 mg every 12 hours or 500 mg/125 mg every 8 hours, depending on infection severity 8
When Dose Adjustment Becomes Necessary
- Dose reduction is only required when CrCl falls below 30 mL/min (severe renal impairment) 7, 8
- For CrCl 10-30 mL/min, reduce the dose by approximately 50% or double the dosing interval 7
- For CrCl <10 mL/min or hemodialysis, further reduction to 25-50% of normal dose is needed, administered after dialysis 7
Monitoring Recommendations
- While dose adjustment is not required at eGFR 47, the FDA label notes that amoxicillin-clavulanate is substantially excreted by the kidney, and monitoring renal function may be useful 8
- The Infectious Diseases Society of America recommends monitoring renal function during treatment in patients approaching the threshold for dose adjustment 9
Important Caveats
Ciprofloxacin-Specific Warnings
- The dose reduction method (maintaining 12-hour intervals with lower doses) is preferable to interval prolongation for ciprofloxacin, as simulations demonstrate faster bacterial eradication with this approach 10
- Avoid administering ciprofloxacin within 2 hours of antacids, calcium, iron, or didanosine due to chelation that markedly decreases drug levels 6
- In severe infections with eGFR 47, a unit dose of 750 mg may be considered at the adjusted intervals with careful monitoring 1