Less painful alternatives for local anesthesia.
BACKGROUND
Infiltration of commonly used local anesthetics is painful. It has been speculated that the pain on infiltration is a direct consequence of the acidity of the anesthetic solution.


OBJECTIVE
To compare the degree of pain of intradermal infiltration and the duration of anesthesia for 1% lidocaine with epinephrine 1:100,000, 1% lidocaine with epinephrine 1:100,000 with 80 meq/L sodium bicarbonate, bacteriostatic saline solution with 1% lidocaine with epinephrine 1:300,000, and bacteriostatic saline solution with 1% lidocaine with epinephrine 1:100,000.


METHODS
The study was performed in three phases: 1) double-blind comparison study, 2 and 3) open clinical trials.


RESULTS
Bacteriostatic saline solution with epinephrine 1:300,000 is significantly less painful on intradermal infiltration than lidocaine with epinephrine 1:100,000 with sodium bicarbonate 80 meq/mL. The saline preparation is an effective anesthetic alternative for superficial surgical procedures such as shave and scissors excision, light curettage and electrodesiccation, and superficial CO2 laser vaporization.


CONCLUSIONS
The pH values of bacteriostatic saline solution with epinephrine 1:300,000 and lidocaine with epinephrine diluted with bacteriostatic saline solution are 5.3 and 4.2, respectively. Both were found to be less painful than 1% lidocaine with epinephrine with sodium bicarbonate 84 meq/mL, which had a pH of 7.4. It is unlikely that the pain of infiltration is a simple function of the pH of the anesthetic solution.
Department of Dermatology, University of Puerto Rico School of Medicine, San Juan 00936-5067.
G
G
Lugo-Janer
M
M
Padial
J L
JL
Sánchez
D000328:Adult; D000368:Aged; D000772:Anesthesia, Local / Q000009:adverse effects*; D001639:Bicarbonates; D002021:Buffers; D004311:Double-Blind Method; D004837:Epinephrine; D006801:Humans; D007271:Injections, Intradermal; D007552:Isotonic Solutions; D008012:Lidocaine / Q000008:administration & dosage / Q000009:adverse effects*; D008875:Middle Aged; D010146:Pain / Q000209:etiology / Q000517:prevention & control*; D011446:Prospective Studies; D012964:Sodium; D017693:Sodium Bicarbonate; D012965:Sodium Chloride
D001639:Bicarbonates; D002021:Buffers; D007552:Isotonic Solutions; D012965:Sodium Chloride; D017693:Sodium Bicarbonate; D008012:Lidocaine; D012964:Sodium; D004837:Epinephrine