What is the dosing for ertapenem (Intramuscular) IM (Intramuscular) injection in patients with Impaired renal function?

Ertapenem IM Dosing in Patients with Impaired Renal Function

For patients with impaired renal function requiring intramuscular ertapenem, the recommended dose is 500 mg daily when creatinine clearance is ≤30 mL/min/1.73 m², while patients with creatinine clearance >30 mL/min/1.73 m² should receive the standard 1 gram daily dose. 1

Dosing Guidelines Based on Renal Function

Normal Renal Function (CrCl >30 mL/min/1.73 m²)

• Standard dose: 1 gram IM once daily 1
• Reconstitute with 3.2 mL of 1% lidocaine HCl injection (without epinephrine) 1
• The resultant concentration is approximately 280 mg/mL
• Use within 1 hour after preparation 1

Severe Renal Impairment (CrCl ≤30 mL/min/1.73 m²)

• Reduced dose: 500 mg IM once daily 1, 2
• Same reconstitution method as standard dose
• No further dose adjustments needed based on severity of renal impairment

End-Stage Renal Disease (CrCl ≤10 mL/min/1.73 m²)

• Dose: 500 mg IM once daily 1
• For patients on hemodialysis: A supplementary dose of 150 mg is recommended if ertapenem is administered within 6 hours prior to hemodialysis 1

Administration Technique

1. Reconstitute 1 gram vial with 3.2 mL of 1% lidocaine HCl injection (without epinephrine) 1
2. Shake vial thoroughly to form solution
3. Immediately withdraw contents and administer by deep intramuscular injection into a large muscle mass (gluteal muscles or lateral part of thigh) 1
4. The reconstituted IM solution must be used within 1 hour after preparation 1

Clinical Considerations

• Ertapenem has a bioavailability of 92% when administered intramuscularly compared to intravenous administration 3
• IM administration is generally well-tolerated when diluted with lidocaine, with injection site tenderness being the most common local reaction 4
• No dose accumulation occurs with daily IM administration over 7 days 3
• When only serum creatinine is available, creatinine clearance can be estimated using the Cockcroft-Gault equation:
  • Males: [(weight in kg) × (140-age in years)] ÷ [(72) × serum creatinine (mg/100 mL)]
  • Females: 0.85 × value calculated for males 1

Important Caveats

• There are no specific data available for IM ertapenem dosing in pediatric patients with renal impairment 1
• No dose adjustments are recommended based on gender, age, weight, or liver disease in adults 5
• The reconstituted IM solution should NEVER be administered intravenously 1
• Local tolerability may be a concern with IM administration, though studies show comparable tolerability to IM ceftriaxone when reconstituted with lidocaine 4

By following these dosing guidelines for ertapenem IM administration in patients with impaired renal function, you can ensure appropriate antimicrobial coverage while minimizing the risk of adverse effects related to drug accumulation.