Oral Augmentin Renal Dose Adjustment
In patients with renal impairment, reduce the dosing frequency of oral Augmentin rather than the individual dose, with specific adjustments based on creatinine clearance (CrCl): for CrCl 10-30 mL/min, use standard dose every 12-24 hours; for CrCl <10 mL/min or hemodialysis, use standard dose every 24 hours with an additional dose after dialysis. 1
Dosing Strategy by Renal Function
Normal Renal Function (CrCl >30 mL/min)
- Standard dosing applies without adjustment
- Common regimens: 500 mg every 8 hours, 875 mg every 12 hours, or 2000 mg (extended-release) every 12 hours
Moderate Renal Impairment (CrCl 10-30 mL/min)
- Reduce frequency to every 12-24 hours while maintaining the standard dose
- Do not use the 875 mg tablet or extended-release formulations
- Example: 500 mg every 12 hours instead of every 8 hours
Severe Renal Impairment (CrCl <10 mL/min)
- Reduce frequency to every 24 hours with standard dose
- Avoid 875 mg tablets and extended-release formulations entirely
- Example: 500 mg every 24 hours
Hemodialysis Patients
- Administer standard dose every 24 hours
- Give an additional dose both during and after dialysis 1
- Timing is critical: dose after dialysis session to prevent premature drug removal and facilitate directly observed therapy
Pharmacokinetic Rationale
The differential clearance of amoxicillin versus clavulanate in renal impairment creates a critical dosing consideration. Research demonstrates that amoxicillin clearance decreases more dramatically than clavulanate clearance as renal function declines 2. This results in a progressively increasing ratio of amoxicillin to clavulanate exposure:
- CrCl 75 mL/min: ratio 4.9
- CrCl 35-75 mL/min: ratio 5.3
- CrCl 10-35 mL/min: ratio 11.9
- CrCl 5-10 mL/min: ratio 13.4
- Hemodialysis: ratio 14.7 2
This differential clearance supports frequency reduction rather than dose reduction, as maintaining adequate clavulanate concentrations is essential for β-lactamase inhibition while preventing amoxicillin accumulation 2.
Critical Pitfalls to Avoid
Do not reduce the individual dose - this is the most common error. The β-lactam pharmacodynamic target requires maintaining concentrations above the MIC for 40-70% of the dosing interval. Reducing the dose compromises efficacy, while extending the interval prevents accumulation 2, 3.
Avoid the 875 mg formulation in any degree of renal impairment - the FDA label explicitly contraindicates this strength when CrCl <30 mL/min due to excessive amoxicillin accumulation risk 1.
Do not use extended-release formulations in renal impairment - these are contraindicated in patients with CrCl <30 mL/min 1.
Monitoring Considerations
- Hepatic function should be monitored at regular intervals in renally impaired patients, as hepatic clearance becomes proportionally more important 1
- Watch for signs of amoxicillin accumulation: rash, crystalluria (rare), or neurologic symptoms in severe cases
- The volume of distribution and bioavailability remain unchanged regardless of renal function 2, so loading doses are not affected by renal impairment
Special Population: Pediatrics
For pediatric patients with renal impairment receiving Augmentin ES-600:
- The same principle applies: reduce frequency, not dose
- Standard pediatric dosing is 90 mg/kg/day divided every 12 hours
- In renal impairment, extend to every 24 hours while maintaining the mg/kg dose 1