[Dermal anesthesia: comparison of the analgesic effects of 2% and 10% lidocaine gel patch].
The analgesic effects of aqueous gel containing 2% or 10% lidocaine with 3% glycyrrhetinic acid mono 3-0 hemiphthalate sodium as an absorption promoter were compared in two volunteer groups of 12 persons each. A round sponge (25 mm in diameter and 1mm in thickness) filled with approximately 0.3g of either gel was applied on the volar surface of the forearm and kept covered with an adhesive plastic film (Tegaderm) for two hours. The analgesic effect was assessed every 30 min by pin-prick method at five places under the coverage for two hours, and after the gel was wiped away. The result from each place was scored 0 (no pain) or 1 (needle pain). The mean pain scores at 1 hr and 1.5 hr in the 10% group were 1.0 and 0.7, and significantly lower than 2.2 and 1.3 of the 2% group (P less than 0.05). Two hour application of the gel, five volunteers in the 2% group and eight volunteers in the 10% group produced a pain score under 1.0. In these subjects, a 26 gauge needle was stuck into the skin for further pain analysis. Four of the 5 subjects in the 2% group and 7 of the 8 subjects in the 10% group did not complain of any pain. Transient local redness under the coverage was observed in 3 subjects in each group. They were all known to be sensitive to alcoholic beverages. No other side effects were found. The plasma concentration of lidocaine was lower than 0.01 microgram.ml-1 at all times.
Nakamura
M
M
Department of Anesthesiology, Kumamoto University Hospital.
Kano
T
T
Hashiguchi
A
A
Shimoda
O
O
Kato
K
K
Shimizu
Y
Y
Morioka
T
T
Mishima
M
M
Yasutake
S
S
Nakano
M
M
D000328:Adult; D000779:Anesthetics, Local / Q000008:administration & dosage*; D005782:Gels; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage*; D012867:Skin / Q000187:drug effects*
D000779:Anesthetics, Local; D005782:Gels; D008012:Lidocaine