What is the recommended reconstitution method for a ceftriaxone 500mg vial?

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Ceftriaxone 500mg Vial Reconstitution

For intramuscular injection, reconstitute the 500mg vial with 1.8 mL of diluent to achieve a 250 mg/mL concentration, or with 1.0 mL to achieve a 350 mg/mL concentration. 1

Reconstitution Procedure

Step-by-Step Instructions

  • Inject the appropriate volume of diluent into the vial and shake thoroughly to form a solution 1
  • Withdraw the entire contents of the vial into a syringe to equal the total labeled dose 1
  • After reconstitution, each 1 mL of solution contains approximately 250 mg or 350 mg equivalent of ceftriaxone, depending on the diluent volume used 1

Diluent Volume Options for 500mg Vial

Concentration Diluent Volume
250 mg/mL 1.8 mL
350 mg/mL 1.0 mL

1

Acceptable Diluents for IM Reconstitution

The following diluents are compatible for intramuscular preparation:

  • Sterile Water for Injection 1
  • 0.9% Sodium Chloride Solution 1
  • 5% Dextrose Solution 1
  • Bacteriostatic Water with 0.9% Benzyl Alcohol 1
  • 1% Lidocaine Solution (without epinephrine) - This option may reduce injection discomfort 2, 1, 3

Critical Considerations

Pain Reduction Strategy

  • Using 1% lidocaine solution as the diluent may significantly reduce the discomfort associated with intramuscular ceftriaxone injection 2
  • Clinical experience demonstrates that lidocaine reconstitution is well tolerated by patients receiving intramuscular ceftriaxone 3

Injection Technique

  • Inject well within the body of a relatively large muscle 1
  • Aspirate before injection to avoid unintentional injection into a blood vessel 1

Stability After Reconstitution

Once reconstituted for IM use at 250 mg/mL or 350 mg/mL concentration:

  • Stable for 24 hours at room temperature (25°C) when using Bacteriostatic Water or 1% Lidocaine 1
  • Stable for 2 days at room temperature when using Sterile Water, 0.9% Sodium Chloride, or 5% Dextrose 1
  • Stable for 3 days when refrigerated (4°C) for all listed diluents 1

Common Pitfalls to Avoid

  • Do not use diluents containing calcium (such as Ringer's solution or Hartmann's solution), as particulate formation can result 1
  • The 350 mg/mL concentration is not recommended for the 250mg vial since it may not be possible to withdraw the entire contents 1
  • Protect the powder from light during storage, though protection from normal light is not necessary after reconstitution 1
  • Discard unused portions after the stability time periods listed above 1

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Intramuscular ceftriaxone in home parenteral therapy.

Antimicrobial agents and chemotherapy, 1988

Professional Medical Disclaimer

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.

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