Safety of Lidocaine 15% and Prilocaine 5% Topical Ointment Used as Local Anesthesia for Intense Pulsed Light Treatment

BACKGROUND: Literature cautions against applying lidocaine 15%/prilocaine 5% over an area larger than 300 cm(2). The area of the face, neck, and chest is 400 cm(2) or greater. OBJECTIVE: To investigate the safety of lidocaine 15%/prilocaine 5% topical anesthetic ointment used as anesthesia for intense pulsed light (IPL) treatment. METHODS AND MATERIALS: Lidocaine 15%/prilocaine 5% ointment was applied to the face only (n=10) for 30 +/- 15 minutes or to the face, neck, and chest (n=10) for a total of 60 +/- 15 minutes before IPL. Blood lidocaine and prilocaine levels were measured. Adverse events were recorded. RESULTS: For the entire cohort, blood was drawn 25.6 +/- 6.6 minutes after IPL was completed. In the face only group, the mean lidocaine level was 0.122 +/- 0.125 microg/mL, and the mean prilocaine level was 0.048 +/- 0.029 microg/mL. In the face, neck, and chest group, the mean lidocaine level was 0.272 +/- 0.208 microg/mL, and the mean prilocaine level was 0.087 +/- 0.060 microg/mL. No adverse events related to systemic toxicity were observed or reported to the nurse. At the 24-hour follow-up, no subject reported symptoms of systemic toxicity after leaving the clinic. CONCLUSION: Under the conditions of this study, topical lidocaine 15%/prilocaine 5% produces low levels of systemic absorption.