Augmentin Dosing in Renal Failure
Augmentin requires dose adjustment in patients with renal impairment, with the specific regimen depending on creatinine clearance (CrCl): for CrCl 10-30 mL/min, reduce frequency to every 12-24 hours; for CrCl <10 mL/min, reduce to every 24 hours; and for hemodialysis patients, give a dose after each dialysis session.
Dosing Algorithm by Renal Function
Mild Renal Impairment (CrCl >30 mL/min)
- No dose adjustment required 1
- Standard dosing applies (typically 500-875 mg every 8-12 hours for adults)
Moderate Renal Impairment (CrCl 10-30 mL/min)
- Reduce dosing frequency to every 12-24 hours 2
- Maintain the milligram dose but extend the interval
- Example: 500 mg every 12 hours or 875 mg every 24 hours
Severe Renal Impairment (CrCl <10 mL/min)
- Reduce to every 24 hours 2
- Consider 500 mg once daily
- Monitor for accumulation, particularly of amoxicillin component
Hemodialysis Patients
- Give dose after each dialysis session 2, 3
- Both amoxicillin and clavulanic acid are removed by hemodialysis, with extraction ratios of 0.44 and 0.74 respectively 3
- Typical regimen: 500 mg after each dialysis session (3 times weekly)
- Timing is critical—administer immediately post-dialysis to avoid premature drug removal
Critical Pharmacokinetic Considerations
The amoxicillin component accumulates more than clavulanic acid in renal failure 2. This creates an important imbalance: the ratio of amoxicillin to clavulanic acid increases dramatically as renal function declines—from 4.9:1 at CrCl 75 mL/min to 14.7:1 in hemodialysis patients 2. This differential accumulation means:
- Amoxicillin clearance is more dependent on renal function than clavulanic acid clearance
- The nonrenal clearance of clavulanic acid partially compensates for reduced kidney function
- Risk of amoxicillin accumulation and toxicity increases disproportionately
Monitoring Requirements
For patients with any degree of renal impairment receiving Augmentin:
- Baseline creatinine clearance calculation (not just serum creatinine)
- Monitor for signs of drug accumulation: neurological symptoms (confusion, seizures with very high levels), gastrointestinal disturbances
- Hepatic function monitoring is also recommended, as the FDA label notes hepatically impaired patients should be dosed with caution 1
- In hemodialysis patients, verify adequate drug levels are maintained between dialysis sessions
Common Pitfalls to Avoid
Don't reduce the dose per administration—extend the interval instead 2. Maintaining adequate peak concentrations is important for β-lactam efficacy.
Don't give Augmentin immediately before hemodialysis—both components will be removed before achieving therapeutic effect 3. Always dose post-dialysis.
Don't assume standard dosing is safe in elderly patients—age-related decline in renal function (even with "normal" creatinine) requires dose adjustment. Calculate actual CrCl using Cockcroft-Gault equation.
Don't interchange different Augmentin formulations in renal failure—the clavulanic acid content varies significantly between formulations (e.g., ES-600 contains 42.9 mg/5mL vs. standard 400 mg/5mL suspension contains 57 mg/5mL) 1.
Evidence Quality Note
The dosing recommendations are based primarily on pharmacokinetic studies 2, 3 and FDA labeling 1, rather than large clinical outcome trials. The research by 2 provides the most comprehensive pharmacokinetic data across the spectrum of renal function and forms the basis for current dosing guidelines. While 4 notes that evidence for dose reduction of many renally cleared antibiotics is limited, the pharmacokinetic data for Augmentin is relatively robust compared to other agents.
The differential clearance of the two components creates a unique challenge not seen with single-agent antibiotics, making individualized dosing based on calculated CrCl essential rather than optional.