What volume of lidocaine 1% is required to mix with one gram of Ceftriaxone (Rocephin)?

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Last updated: April 18, 2025 • View editorial policy

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From the Guidelines

To reconstitute one gram of rocephin (ceftriaxone), you need 3.5 cc of 1% lidocaine. This is based on the standard practice for intramuscular administration of rocephin when pain management is desired, as some health-care providers believe that the discomfort of the injection may be reduced by using 1% lidocaine solution as a diluent 1. The lidocaine serves as a diluent that reduces injection site pain while not affecting the antimicrobial efficacy of the ceftriaxone.

  • Key points to consider when reconstituting rocephin with lidocaine include:
    • The resulting solution should be administered within 24 hours if kept at room temperature or within 3 days if refrigerated.
    • Lidocaine should only be used for intramuscular injections of rocephin and never for intravenous administration.
    • The solution should be inspected for particles and discoloration before administration. It's worth noting that the use of lidocaine as a diluent for ceftriaxone is a common practice, although the provided study 1 does not specifically address the volume of lidocaine needed for reconstitution. However, based on standard medical practice and the goal of minimizing injection site pain, 3.5 cc of 1% lidocaine is the recommended volume for reconstituting one gram of rocephin.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Calculation of Lidocaine Volume

To determine the volume of lidocaine 1% needed for one gram of ceftriaxone (rocephine), we can refer to the studies that provide information on the dilution of ceftriaxone with lidocaine.

  • The study 2 mentions that ceftriaxone 500 mg was administered in either 2 or 1.4 mL of lidocaine 1% solution, resulting in final ceftriaxone concentrations of 250 and 350 mg/mL, respectively.
  • Another study 3 states that 1 g of ceftriaxone was dissolved in 3.5 mL of 1% lidocaine for intramuscular injection.

Lidocaine Volume for 1g Ceftriaxone

Based on the information from study 3, for 1 gram of ceftriaxone, 3.5 mL of lidocaine 1% is used.

  • This translates to approximately 35 mL of lidocaine 1% per 10 grams of ceftriaxone.
  • To calculate the volume of lidocaine needed for 1 gram of ceftriaxone, we can use the ratio from study 3, which is 3.5 mL of lidocaine per 1 gram of ceftriaxone.

Key Points

  • The volume of lidocaine 1% needed for one gram of ceftriaxone is 3.5 mL, as indicated in study 3.
  • This information is specific to the preparation of ceftriaxone for intramuscular injection, as described in the studies 2 and 3.

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.