What is the recommended Ertapenem dose for a patient with a GFR of 29?

Ertapenem Dosing for GFR 29 mL/min/1.73 m²

For a patient with a GFR of 29 mL/min/1.73 m², ertapenem should be dosed at 500 mg once daily, as this falls into the category of severe renal impairment (creatinine clearance ≤30 mL/min/1.73 m²) requiring dose reduction from the standard 1 gram daily dose. 1

FDA-Approved Dosing Guidelines

The FDA label provides clear guidance for renal dosing 1:

• GFR >30 mL/min/1.73 m²: No dosage adjustment necessary; use standard 1 gram daily
• GFR ≤30 mL/min/1.73 m² (severe renal impairment): 500 mg once daily
• GFR ≤10 mL/min/1.73 m² (end-stage renal disease): 500 mg daily

Since your patient has a GFR of 29 mL/min/1.73 m², this falls just below the 30 mL/min/1.73 m² threshold, requiring the reduced dose of 500 mg daily 1.

Critical Safety Considerations

Neurotoxicity Risk at This GFR Level

Exercise extreme caution when prescribing ertapenem at GFR 29 mL/min/1.73 m², as even the recommended reduced dose of 500 mg daily carries significant risk of neurotoxicity in patients with advanced chronic kidney disease. 2, 3

Multiple case reports demonstrate that the FDA-recommended 500 mg daily dose may still be excessive for patients with Stage 4-5 CKD 2, 3:

• Patients with GFR <30 mL/min/1.73 m² developed acute reversible peripheral neuropathy within 1 week of treatment with renal-adjusted doses 2
• Two patients with Stage 5 CKD developed progressive hallucinations, asterixis, myoclonic jerks, and cognitive impairment after only 4-5 days of the recommended 500 mg daily dose 3
• Plasma ertapenem levels measured 24 hours after the last dose reached 53.7 mg/L (therapeutic MIC90 is only 2 mg/L), indicating massive drug accumulation 3
• Neurologic manifestations persisted for 2 weeks despite drug cessation and high-flux hemodialysis 3

Clinical Monitoring Protocol

Monitor closely for early signs of neurotoxicity 2, 4, 3:

• Peripheral neuropathy: Paresthesias, weakness, sensory changes
• Central nervous system toxicity: Confusion, hallucinations, cognitive dysfunction, myoclonic jerks, asterixis, seizures
• Timeline: Symptoms typically develop within 3-7 days of treatment initiation

If any neurologic symptoms develop, immediately discontinue ertapenem 2, 4, 3. Complete clinical recovery typically occurs within 2 weeks of cessation 2.

Alternative Dosing Consideration

Given the documented neurotoxicity risk at 500 mg daily in patients with GFR <30 mL/min/1.73 m², consider 3:

• Further dose reduction below 500 mg daily may be warranted, though specific recommendations are not established
• Shorter treatment duration if clinically feasible
• Alternative antibiotics with safer renal profiles should be strongly considered

Hemodialysis Patients (If Applicable)

If the patient progresses to hemodialysis 1, 5:

• Administer 500 mg daily as the base dose 1
• Give a supplementary dose of 150 mg if ertapenem is administered within 6 hours prior to hemodialysis 1
• If given ≥6 hours before hemodialysis, no supplementary dose is needed 1
• Alternative practical regimen: 500 mg thrice weekly after each hemodialysis session maintains plasma concentration above 2 mg/L 5

Bottom Line

Use 500 mg once daily per FDA guidance, but maintain heightened vigilance for neurotoxicity throughout treatment, as this dose may still be excessive at GFR 29 mL/min/1.73 m². 1, 2, 3 Consider alternative antibiotics if available and appropriate for the infection being treated.