[Dermal patch anesthesia to prevent pain from dermal puncture--10% lidocaine aqueous gel with 3% glycyrrhetinic acid 3-0 hemiphthalate disodium].

The clinical efficacies of 10% lidocaine aqueous gel with and without 3% glycyrrhetinic acid 3-0 hemiphthalate disodium (GAHPh) applied as a skin patch for reduction of pain from venous cannulation were evaluated in a double blind study. Twenty-four adult patients, who were scheduled for surgery under general anesthesia, gave informed consent to participate in this study. The patients were allocated randomly into two groups: one for a dermal patch GAHPh (GAHPh group) and the other for a dermal patch without GAHPh (plain group). Approximately 0.3g of either gel with or without GAHPh, soaked in a round sponge (25mm in diameter, 1mm in thickness), was applied over the selected vein on the arm and was covered with an adhesive plastic film (Tegaderm). Pain score was graded by the number of painful spots out of the 5 tests in the treated skin area. In patients with a pain score under 1, venous cannulation was carried out without an intradermal injection of a local anesthetic and pain associated with the cannulation procedure was graded by patients on a scale of 5, where 0 = no pain, 1 = little pain, 2 = moderate pain, 3 = painful, 4 = very painful. The mean application time periods were 59.3 min for the GAHPh group and 60.3 min for the plain group. Transient local redness was observed in 8 patients after removal of the gels; 3 in the GAHPh group and 5 in the plain group. The mean pain score (1.3 +/- 1.5) in the GAHPh group, was significantly lower than that (2.5 +/- 1.7) in the plain group (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)