What is the recommended reconstitution volume of ertapenem with lidocaine (local anesthetic) when 3.2 ml of lidocaine is used?

Ertapenem Reconstitution with Lidocaine

When reconstituting ertapenem for intramuscular administration, 3.2 mL of 1% lidocaine HCl injection (without epinephrine) should be used, resulting in a concentration of approximately 280 mg/mL. 1

Proper Reconstitution Procedure

• Ertapenem must be reconstituted prior to administration when using the intramuscular route 1
• For intramuscular administration, reconstitute the contents of a 1 g vial of ertapenem with exactly 3.2 mL of 1% lidocaine HCl injection (without epinephrine) 1
• Shake the vial thoroughly to form solution, which will result in a concentration of approximately 280 mg/mL 1
• The reconstituted IM solution should be used within 1 hour after preparation 1
• After reconstitution, immediately withdraw the contents of the vial and administer by deep intramuscular injection into a large muscle mass (such as the gluteal muscles or lateral part of the thigh) 1

Important Considerations and Precautions

• The reconstituted solution with lidocaine should NEVER be administered intravenously 1
• Due to the use of lidocaine HCl as a diluent, ertapenem administered intramuscularly is contraindicated in patients with a known hypersensitivity to local anesthetics of the amide type 1
• For pediatric patients 3 months to 12 years of age, the same reconstitution volume (3.2 mL of 1% lidocaine) should be used, but the dose administered should be 15 mg/kg of body weight (not to exceed 1 g/day) 1
• Discard any unused portion of the reconstituted solution 1

Safety Considerations When Using Lidocaine

• When using lidocaine for reconstitution, be aware of the maximum safe dose limits for lidocaine (7 mg/kg with epinephrine, 4.5 mg/kg without epinephrine in adults) 2
• Avoid using ertapenem with lidocaine in patients who have recently received other local anesthetic interventions, as combining local anesthetics increases risk of toxicity 2
• Intravenous lidocaine should not be started within 4 hours of any nerve or fascial plane block, or infiltration of local anesthetic 2
• Be vigilant for signs of local anesthetic systemic toxicity, which may include circumoral numbness, facial tingling, slurred speech, metallic taste, auditory changes, and hallucinations 2

Clinical Evidence for Intramuscular Administration

• Clinical studies have shown that ertapenem 1 g reconstituted in lidocaine and administered intramuscularly once daily is generally well tolerated 3
• In comparative studies, only 1.1% of patients receiving IM ertapenem (reconstituted with lidocaine) experienced moderate to severe injection site symptoms, compared to 10.0% in a ceftriaxone group 3
• The most common local injection site symptoms are tenderness and pain 3

By following these reconstitution guidelines, you can ensure proper preparation and administration of ertapenem for intramuscular use while minimizing patient discomfort and maintaining drug efficacy.