Preparation of 1.5% Lidocaine Solution

Detailed Preparation Method

To prepare 10 ml of 1.5% lidocaine solution, calculate the required volumes using the formula: C₁V₁ = C₂V₂, where C₁ is the initial concentration (2%), V₁ is the initial volume, C₂ is the target concentration (1.5%), and V₂ is the final volume, then take 7.5 ml of 2% lidocaine solution and add 2.5 ml of sterile diluent, yielding 10 ml of 1.5% lidocaine solution 1, 2
Ensure sterile technique is maintained throughout the preparation process to prevent contamination 1, 3

Use appropriate sterile syringes for measuring and mixing the solution 1, 4
Prepare the solution immediately before use for optimal efficacy 1, 5
Label the prepared solution clearly with medication name and concentration (1.5% lidocaine), date and time of preparation, and expiration time 1, 2
Refrigerate the prepared solution if not used immediately and discard after 24 hours 1
Shake well before use to ensure proper mixing 1, 3

The 1.5% concentration is commonly used for local infiltration anesthesia and nerve blocks 2

Always verify calculations before preparing the solution to prevent medication errors 2
Remember that the maximum safe dose of lidocaine is 4.5 mg/kg without epinephrine and 7 mg/kg with epinephrine 2
Monitor for signs of lidocaine toxicity including perioral tingling, tinnitus, light-headedness, and restlessness 2
Have lipid emulsion 20% readily available in case of lidocaine toxicity 2

For procedures such as paracervical block during IUD insertion, lidocaine can be injected at specific sites using a 22- or 25-gauge 1.5" needle, as recommended by the American College of Obstetricians and Gynecologists 6