A COMPARATIVE-STUDY OF TRANSDERMAL 10-PERCENT LIDOCAINE GEL WITH AND WITHOUT GLYCYRRHETINIC ACID MONOHEMIPHTHALATE DISODIUM FOR PAIN REDUCTION AT VENOUS CANNULATION

The clinical benefits of transdermal 10% lidocaine base gels with and without 3% glycyrrhetinic acid monohemiphthalate disodium (GAMHPh) for reduction of pain at venous cannulation were compared in a randomized , double-blind fashion in 24 surgical patients. After about 60 min of occlusive transdermal application, the mean pinprick pain score (1.3 /- 1.5) in the GAMHPh group (n = 12), graded by noting the number of p ainful pinpricks out of five, was significantly less than that (2.5 +/ - 1.7) in the control group (n = 12) (P < 0.05). Twelve patients (eigh t in the GAMHPh group and four in the control group) who had a pinpric k score less than 1 underwent venous cannulation without intradermal i njection of a local anesthetic. The pain score at venipuncture, graded by the patients on a scale of 5, was significantly less in the GAMHPh group than that in the control group (1.9 +/- 1.1 vs 3.3 +/- 1.0, P < 0.05). Erythema observed in 8 of the 24 patients was the only adverse local reaction. Addition of 3% GAMHPh to the lidocaine gel is useful in promoting transdermal lidocaine absorption.