Co-amoxiclav Dosing with Creatinine 1.2 mg/dL
No dosage adjustment is required for co-amoxiclav (amoxicillin/clavulanate) when serum creatinine is 1.2 mg/dL, as this represents mild renal impairment with creatinine clearance typically >30 mL/min. 1
Assessment of Renal Function
- A serum creatinine of 1.2 mg/dL does not automatically indicate significant renal impairment, as creatinine clearance provides a more accurate assessment than serum creatinine alone 2
- Calculate creatinine clearance using the Cockcroft-Gault equation to determine the actual degree of renal function, as patients can have significantly decreased glomerular filtration rates despite near-normal creatinine levels 2
- For most patients with creatinine 1.2 mg/dL, the calculated creatinine clearance will exceed 50 mL/min, placing them in the normal to mild impairment category 1
Standard Dosing Recommendations
Standard dosing regimens (typically 500/125 mg three times daily or 875/125 mg twice daily) can be used for patients with creatinine clearance >30 mL/min. 1
- The Infectious Diseases Society of America supports standard dosing for normal to mild renal impairment 1
- Population pharmacokinetic studies in critically ill patients demonstrate that standard dosing regimens (1 g four times daily or 2 g three times daily intravenously) are appropriate for most patients except those with creatinine clearance >190 mL/min 3
When Dose Adjustment Becomes Necessary
Dosage modifications are only required when renal function deteriorates further:
- Moderate to severe impairment (CrCl 10-30 mL/min): Reduce dosage by approximately 50% or double the dosing interval 1
- End-stage renal disease (CrCl <10 mL/min): Reduce to 25-50% of normal dose 1
- Hemodialysis patients: Administer dose after dialysis session to avoid premature drug removal 1
Monitoring Considerations
- Patients with borderline renal function (creatinine 1.2-1.5 mg/dL) may benefit from 24-hour urine collection to accurately define the degree of impairment before making regimen changes 1
- Close monitoring for adverse effects is warranted, as drug accumulation can occur with any degree of renal insufficiency 1
- Serum creatinine alone underestimates renal impairment compared to calculated creatinine clearance, particularly in elderly patients and those with reduced muscle mass 2
Common Pitfalls to Avoid
- Do not assume all antibiotics require the same degree of dosage adjustment in renal impairment—co-amoxiclav specifically requires adjustment only when CrCl falls below 30 mL/min 1, 4
- Avoid relying solely on serum creatinine without calculating creatinine clearance, as this may miss clinically significant renal impairment 2
- Do not prematurely reduce doses in patients with mild elevations in creatinine (1.2-1.5 mg/dL) without first confirming reduced creatinine clearance, as this may result in subtherapeutic drug levels 4