Title: High-energy pulsed light source hair removal device used to evaluate the onset of action of a new topical anesthetic.
Authors: Altman DA, Gildenberg SR
Journal: Dermatol Surg 1999 Oct;25(10):816-8
Affiliated institution: Division of Dermatology, St. John’s Macomb Hospital Center, Warren, Michigan, USA.
BACKGROUND: Topical anesthetic agents are widely used to mitigate the pain associated with laser and high-energy pulsed light source hair removal. OBJECTIVE: To evaluate the relative efficacy and onset of action of a new topical anesthetic agent, ELA-Max cream (lidocaine 4%), relative to a widely used agent, EMLA cream (lidocaine 2.5%/prilocaine 2.5%). METHODS: ELA-Max and EMLA were applied to the forearms of 10 unblinded test subjects. The EMLA-treated sites were occluded for 1.5 hours prior to testing. The ELA-Max-treated sites were unoccluded and the cream was applied immediately prior to testing. Pulses from an Epilight high-energy pulsed light source were then administered 1.5 hours after occlusion with EMLA and in 5-minute intervals after application of ELA-Max. Pain scores were recorded on a visual analog scale (VAS). RESULTS: Six of 10 patients reported some anesthetic effect from ELA-Max after 5 minutes of unoccluded skin contact. Seven of 10 subjects reported maximal pain control 20 minutes after application of unoccluded ELA-Max, roughly equivalent to EMLA after 1.5 hours of occlusion. CONCLUSION: ELA-Max is an effective topical anesthetic agent comparable to EMLA under occlusion. It appears to be faster acting than EMLA, and along with its effectiveness without occlusion, may be an easier agent to use.