Reconstituting Rocephin (Ceftriaxone) with Lidocaine
Reconstitute ceftriaxone with 1% lidocaine solution when administering intramuscularly to reduce injection pain. 1
Standard Reconstitution Practice
- Use 1% lidocaine (without epinephrine) as the diluent for intramuscular ceftriaxone administration. 1, 2
- The 1% lidocaine concentration has been extensively studied and proven to significantly reduce pain intensity and frequency at the injection site without altering ceftriaxone's pharmacokinetics or bioavailability. 2
- Clinical studies demonstrate that lidocaine as a diluent makes intramuscular ceftriaxone well tolerated by patients, with cure rates of 97% (30/31 patients) in home parenteral therapy settings. 3
Volume Considerations
- The specific volume of 1% lidocaine needed depends on the ceftriaxone dose being reconstituted, but standard practice uses enough diluent to create an appropriate concentration for intramuscular injection. 2
- For a 0.5 g dose of ceftriaxone, studies used 1% lidocaine as the complete diluent with excellent results. 2
- For 1 g doses, similar reconstitution with 1% lidocaine has been validated in comparative trials. 4
Clinical Evidence Supporting This Practice
- Pharmacokinetic studies confirm that 1% lidocaine does not alter ceftriaxone's elimination parameters, with identical mean peak plasma concentrations (42-45 mcg/mL), time to peak (2.5-3 hours), area under the curve (577-578 mcg·h/mL), and elimination half-life (7.0-7.1 hours) whether reconstituted in water or 1% lidocaine. 2
- The CDC's 1993 STD treatment guidelines specifically note that some healthcare providers believe the discomfort of ceftriaxone injection may be reduced by using 1% lidocaine solution as a diluent. 1
- Comparative studies show that ceftriaxone reconstituted in lidocaine has tolerability profiles comparable to other intramuscular antibiotics, with only 35.6% of patients experiencing mild injection site symptoms (primarily tenderness). 4
Important Safety Considerations
- Do not use lidocaine with epinephrine for reconstitution, as the standard practice uses plain 1% lidocaine. 1, 2
- Ensure you are using sterile 1% lidocaine solution appropriate for injection. 2
- This reconstitution method is specifically for intramuscular administration only—intravenous ceftriaxone should never be reconstituted with lidocaine. 1