What is the stability of ceftriaxone (Ceftriaxone) 1g after reconstitution with lidocaine (Lidocaine)?

Stability of Ceftriaxone 1g After Reconstitution with Lidocaine

Ceftriaxone 1g reconstituted with 1% lidocaine solution (without epinephrine) remains stable for 24 hours at room temperature (25°C) and 10 days when refrigerated at 4°C. 1

Storage and Stability Guidelines

Room Temperature Storage (25°C)

• Ceftriaxone reconstituted with 1% lidocaine maintains >90% potency for 24 hours at room temperature 1
• Solutions at concentrations of 100 mg/mL, 250 mg/mL, and 350 mg/mL all demonstrate equivalent stability profiles 1
• After 24 hours at room temperature, unused portions should be discarded 1

Refrigerated Storage (4°C)

• When refrigerated, ceftriaxone-lidocaine solutions remain stable for up to 10 days at concentrations of 100 mg/mL 1
• At higher concentrations (250 mg/mL and 350 mg/mL), refrigerated stability is reduced to 3 days 1
• Refrigeration significantly extends usable shelf life compared to room temperature storage 1

Reconstitution Specifications

Standard Concentrations

• For 1g vials, add 3.6 mL of 1% lidocaine to achieve 250 mg/mL concentration 1
• For 1g vials, add 2.1 mL of 1% lidocaine to achieve 350 mg/mL concentration 1
• The lidocaine solution must be without epinephrine 1

Visual Inspection Requirements

• Solutions should range from light yellow to amber in color, depending on storage duration and concentration 1
• Protection from normal light is not necessary after reconstitution 1
• Inspect visually for particulate matter before administration 1

Clinical Application and Tolerability

Pain Reduction Benefits

• Reconstitution with lidocaine significantly improves tolerability of intramuscular ceftriaxone administration 2, 3, 4
• The 1993 CDC guidelines note that some healthcare providers believe lidocaine as a diluent reduces injection discomfort 2
• Clinical studies demonstrate that when lidocaine is used for reconstitution, the intramuscular route is well tolerated by all patients 3

Comparative Safety Data

• In a randomized controlled trial, ceftriaxone reconstituted in lidocaine showed comparable tolerability to other antibiotics similarly prepared 4
• Moderate to severe injection site symptoms occurred in only 10% of patients receiving IM ceftriaxone with lidocaine 4
• The most common local symptoms were tenderness and pain, which were generally mild 4

Critical Stability Considerations

Temperature Monitoring

• Stability is highly temperature-dependent; solutions exposed to 37°C lose potency more rapidly 5, 6
• At body temperature (37°C), stability is reduced to approximately 6 hours for standard concentrations 1
• Maintaining controlled room temperature or refrigeration is essential for preserving drug potency 1

Do Not Freeze

• Ceftriaxone-lidocaine solutions should not be frozen 1
• Freezing is only appropriate for ceftriaxone reconstituted with dextrose or sodium chloride solutions, not lidocaine 1

Common Pitfalls to Avoid

Incompatible Diluents

• Never use calcium-containing diluents (Ringer's solution, Hartmann's solution) with ceftriaxone, as particulate formation will result 1
• Do not mix ceftriaxone solutions with vancomycin, aminoglycosides, amsacrine, or fluconazole in the same container 1

Storage Duration Errors

• The most common error is exceeding the 24-hour room temperature stability window 1
• Healthcare providers must clearly label reconstitution time and discard solutions beyond stability limits 1
• Different concentrations have different refrigerated stability periods (10 days for 100 mg/mL vs. 3 days for 250-350 mg/mL) 1

Concentration-Specific Stability

• Higher concentrations (250-350 mg/mL) have shorter refrigerated stability (3 days) compared to lower concentrations (100 mg/mL, 10 days) 1
• This concentration-dependent stability must be considered when preparing solutions for outpatient or home therapy 3