Comparison of cutaneous anesthetic effect of 8% lidocaine spray with lidocaine patch using current perception threshold test.

OBJECTIVE

A lidocaine patch is often used for topical anesthesia prior to venipuncture, but needs to be applied for several hours before the puncture, and the site is fixed. A metered-dose lidocaine pump spray could be used to produce cutaneous topical anesthesia. In this study, we compared the anesthesia between the spray and the patch.

DESIGN

Thirteen healthy male volunteers received three treatments of metered-dose 8% lidocaine spray, a lidocaine patch, and no application as control measurement, in a random order separated by at least 2 days. Each treatment was applied topically on the forearm. Sensory nerve fibers (Abeta, Adelta, and C fibers) were evaluated with a series of 5, 250, and 2,000 Hz stimuli using current perception threshold (CPT) before and 30 minutes after each application.

RESULTS

Under the control condition, CPTs measured at baseline and at 30 minutes were similar for 2,000 and 250 Hz stimuli, but significantly reduced for 5 Hz stimulation at 30 minutes. Under patch application, CPTs for 2,000 and 250 Hz stimuli at 30 minutes after application were significantly higher than baseline, while CPTs for 5 Hz stimulation at baseline and 30 minutes after application were similar. Under spray application, CPTs for all stimuli at 30 minutes were significantly higher than baseline.

CONCLUSIONS

Similar to the lidocaine patch, the lidocaine spray produces cutaneous weak anesthesia at 30 minutes after treatment. The spray seems to produce local anesthesia faster than the patch.