Neutralized lidocaine with epinephrine for local anesthesia--II.

The pain usually associated with intradermal injection of lidocaine and epinephrine is significantly attenuated by the addition of either sodium bicarbonate or sodium hydroxide to 1% lidocaine with epinephrine. This suggests that sodium bicarbonate attenuates pain by increasing the pH of the anesthetic solution. The clinical effects of a solution of lidocaine (1%) with epinephrine (1:100,000) and sodium bicarbonate (80 meq/L) were assessed after infiltration in skin. Anesthetic stored for 1 week caused nearly equal areas of anesthesia and vasoconstriction as an identical solution prepared on the day of use.