Decreasing the pain of local anesthesia: a prospective, double-blind comparison of buffered, premixed 1% lidocaine with epinephrine versus 1% lidocaine freshly mixed with epinephrine.
BACKGROUND
Local anesthetics are acidic and cause pain on infiltration into the skin. Two methods are commonly used by dermatologists to raise the pH of lidocaine with epinephrine: buffering with sodium bicarbonate or freshly mixing lidocaine with epinephrine on the day of use.


OBJECTIVE
Our purpose was to compare the pain induced by infiltration of the skin with 1% lidocaine with epinephrine 1:100,000 buffered with sodium bicarbonate (buffered) versus 1% lidocaine freshly mixed with epinephrine (fresh).


METHODS
Sixty volunteers were recruited for this prospective, double-blind study. Each subject received an intradermal injection of the buffered solution and the fresh solution. Immediately after each injection subjects rated the pain of infiltration on a 100-mm visual analog scale. The pain scores for the anesthetic solutions were compared using the paired t test.


RESULTS
The pain score for the buffered solution was 18.3 +/- 20.3, and the pain score for the fresh solution was 23.5 +/- 19.1 (P = .0543). Sixty-five percent of subjects felt the fresh solution was more painful than the buffered solution.


CONCLUSIONS
The results did not reach statistical significance.


CONCLUSIONS
In this small study, buffered lidocaine with epinephrine caused less pain on infiltration into the skin than lidocaine freshly mixed with epinephrine, but the results were not statistically significant.
Burns
Carrine A
CA
Department of Dermatology, University of Rochester, Rochester, New York, USA.
Ferris
Georgette
G
Feng
Changyong
C
Cooper
Jennifer Z
JZ
Brown
Marc D
MD
D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects*; D002021:Buffers; D004311:Double-Blind Method; D004338:Drug Combinations; D004837:Epinephrine / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007271:Injections, Intradermal; D008012:Lidocaine / Q000008:administration & dosage / Q000009:adverse effects*; D010146:Pain / Q000139:chemically induced* / Q000503:physiopathology; D010147:Pain Measurement; D017693:Sodium Bicarbonate; D012996:Solutions / Q000737:chemistry
D000779:Anesthetics, Local; D002021:Buffers; D004338:Drug Combinations; D012996:Solutions; D017693:Sodium Bicarbonate; D008012:Lidocaine; D004837:Epinephrine