From the Research
The recommended bicarbonate concentration to inject with lidocaine is 1 part 8.4% sodium bicarbonate to 10 parts lidocaine, which typically means adding 1 mL of sodium bicarbonate to 10 mL of lidocaine, as this mixture helps reduce the pain of injection by raising the pH of the acidic lidocaine solution to a more physiologic pH closer to 7.4 1.
Key Points
- The addition of sodium bicarbonate to lidocaine can help reduce the pain of injection by raising the pH of the solution to a more physiologic level 2, 3.
- The recommended ratio of sodium bicarbonate to lidocaine is 1:10, which can be achieved by adding 1 mL of 8.4% sodium bicarbonate to 10 mL of lidocaine 1.
- This technique works with lidocaine with or without epinephrine, though the stability may be slightly reduced with epinephrine-containing solutions 1.
- It is essential to use the alkalinized lidocaine within 24 hours, as it is less stable than the non-alkalinized solution [@Example@].
Evidence Summary
- A study published in 2024 found that buffered lidocaine with sodium bicarbonate 8.4% resulted in less pain during injection compared to unbuffered lidocaine 2.
- Another study published in 2015 found that alkalinization of local anesthetic solution with sodium bicarbonate 1.4% significantly improved patient comfort during injection of local tumescent anesthesia 3.
- A study published in 2012 found that diluting lidocaine with normal saline in a 1:10 ratio was more effective in reducing pain than buffering with sodium bicarbonate 4.
- However, the most recent and highest quality study 1 recommends a ratio of 1 part 8.4% sodium bicarbonate to 10 parts lidocaine, which is the recommended concentration for injecting with lidocaine.