Dilution Requirements for Neodrol (Lidocaine) Injection
Dilution of Neodrol (lidocaine) injection is NOT required for most standard anesthetic procedures, but dilution IS necessary in specific clinical situations to achieve lower concentrations or adequate volumes for certain regional anesthesia techniques. 1
When Dilution is NOT Required
The FDA-approved labeling for lidocaine hydrochloride injection (Neodrol) provides ready-to-use concentrations for most procedures without requiring dilution 1:
- Standard concentrations (0.5%, 1.0%, 1.5%, 2.0%) are supplied ready for direct administration for infiltration, peripheral nerve blocks, and epidural anesthesia 1
- Percutaneous infiltration: 0.5% or 1.0% solutions used directly (1-60 mL, 5-300 mg total) 1
- Peripheral nerve blocks: 1.5% solution for brachial plexus blocks (15-20 mL, 225-300 mg) 1
- Epidural anesthesia: 1.0%, 1.5%, or 2.0% concentrations administered without dilution 1
When Dilution IS Required
Dilution with 0.9% sodium chloride injection is necessary in the following situations 1:
For Lower Concentrations
- Intravenous regional anesthesia in children: Dilute to 0.25-0.5% concentrations to avoid systemic toxicity (maximum 3 mg/kg or 1.4 mg/lb) 1
- When the lowest effective concentration is needed: "In some cases it will be necessary to dilute available concentrations with 0.9% sodium chloride injection in order to obtain the required final concentration" 1
For Adequate Volume
- Epidural test doses: May require dilution to achieve appropriate volume (2-3 mL of 1.5% lidocaine) 1
- Continuous epidural infusions: Concentration should not exceed 2 mg/mL and should be diluted with D5W for infusion 1
Critical Administration Principles
Fractional Dosing Technique
- Avoid rapid injection of large volumes through epidural catheters 1
- Administer fractional doses when feasible, allowing adequate time for onset assessment between doses 1
Maximum Dosing Constraints
- Without epinephrine: Maximum 4.5 mg/kg (not to exceed 300 mg total) 1
- With epinephrine: Maximum 7 mg/kg (not to exceed 500 mg total) 1
- Continuous epidural: Do not repeat maximum dose at intervals less than 90 minutes 1
Common Pitfalls to Avoid
Never use disinfecting agents containing heavy metals (mercury, zinc, copper) on vial stoppers, as these cause swelling and edema 1. Instead, use 91% isopropyl alcohol or 70% ethyl alcohol for chemical disinfection 1.
Always inspect solutions visually before administration—discard any solutions with particulate matter or discoloration 1.
Do not confuse concentration percentages with volume requirements—calculate total milligram dose carefully based on patient weight and clinical indication 1.