Augmentin Dosing in Stage 3b Chronic Kidney Disease
For patients with CKD stage 3b (GFR 30-44 mL/min), reduce Augmentin to 375 mg twice daily instead of the standard three times daily dosing to prevent drug accumulation and toxicity. 1
Rationale for Dose Adjustment
Stage 3b CKD represents moderate to severe renal impairment with GFR between 30-44 mL/min, which significantly affects the elimination of both amoxicillin and clavulanic acid components of Augmentin. 1
Pharmacokinetic Considerations
Both amoxicillin and clavulanic acid are primarily renally cleared, making dose adjustment essential in renal impairment to avoid accumulation. 2
In patients with end-stage renal disease, the total serum clearance of both components is substantially reduced compared to patients with normal renal function, demonstrating the critical impact of kidney function on drug elimination. 2
The terminal half-life of amoxicillin increases dramatically from approximately 1 hour in normal patients to 13.6 hours in severe renal impairment, while clavulanic acid half-life increases to 3.05 hours. 2
Specific Dosing Protocol
Standard dose reduction: Augmentin 375 mg (or 500/125 mg formulation) twice daily for GFR 30-44 mL/min. 1
Additional Considerations for More Severe Impairment
If GFR falls below 30 mL/min, further dose reduction or extended interval dosing becomes necessary. 1
Dosage adjustments should be calculated based on creatinine clearance or GFR using validated calculators rather than manual estimation. 3
Clinical Monitoring
Renal function should be monitored before initiating therapy and periodically during treatment, as drug dosing errors are common in patients with renal impairment and can lead to adverse effects. 3
The risk of drug accumulation increases with declining renal function, potentially causing toxicity if standard dosing is maintained. 4
Common Pitfall to Avoid
Do not use standard three-times-daily dosing in stage 3b CKD patients, as this will lead to excessive drug accumulation given the prolonged half-lives of both amoxicillin and clavulanic acid in renal impairment. 2 The reduced clearance affects not only renal excretion but also nonrenal clearance mechanisms, making dose adjustment critical even though some hepatic metabolism occurs. 2