Serum lidocaine levels and cutaneous side effects after application of 23% lidocaine 7% tetracaine ointment to the face.

ABSTRACT

BACKGROUND: Few published studies have analyzed serum lidocaine levels and individual patient characteristics affecting metabolism after application of compounded topical anesthetics. OBJECTIVE: To measure serum lidocaine levels during and cutaneous side effects after standardized application of 23% lidocaine/7% tetracaine compounded anesthetic to the face of healthy volunteers. METHODS AND MATERIALS Fifty-two volunteers were enrolled, and compounded 23% lidocaine/7% tetracaine ointment was applied to their faces for 2 hours. Lidocaine levels were determined every 30 minutes during application and for 2 hours after removal. Follow-up telephone calls 3 days later assessed cutaneous side effects. RESULTS: Median peak lidocaine level was 1.15 µg/mL, and the highest peak lidocaine level in an individual was 3.4 µg/mL. Higher serum lidocaine levels were found in men (p < .01), nonwhite volunteers (p = .02), and those with larger facial surface area (p = .04). Age and body mass index did not affect lidocaine levels. Irritant contact dermatitis was common, resulting in hyperpigmentation in some patients. CONCLUSION: Facial surface area, male sex, and nonwhite ethnicity were associated with higher serum lidocaine levels after topical application of lidocaine. Compounded anesthetics containing lidocaine should be used with caution under the direct supervision of a physician.