Lidocaine iontophoresis for local anesthesia before shave biopsy.

BACKGROUND

Lidocaine iontophoresis is a method of topical anesthesia in which lidocaine is driven into the skin under the influence of electric current.

OBJECTIVE

To compare lidocaine iontophoresis to placebo for topical anesthesia before shave biopsy in adult patients.

METHODS

This was a single-center, double-blind, placebo-controlled evaluation of iontophoresis of 2% lidocaine with 1:100,000 epinephrine in patients undergoing shave biopsy. Patients were evaluated for sensation to pinprick after iontophoresis. After completion of the procedure, those patients who did not receive supplemental lidocaine rated the pain associated with the procedure using a 10-cm visual analog scale. The investigator also evaluated the patient's pain after biopsy. Treatment sites were examined for evidence of adverse events such as erythema, urticaria, or burns.

RESULTS

Forty-one patients undergoing shave biopsy for evaluation of skin lesions were enrolled. Nineteen of 21 patients in the lidocaine group versus 2 of 20 placebo patients required no supplemental anesthesia (P<0.001). The pain reported by the patient on the visual analog scale subsequent to the procedure was significantly lower in the lidocaine group (P<0.001). In concordance with the results reported by the patients, investigators rated pain lower in the lidocaine group (P<0.001). Blanching and/or erythema occurring at the iontophoresis-treated site in 37 of 41 patients resolved within 1 hour. There were no other treatment-related events.

CONCLUSIONS

Lidocaine iontophoresis is a safe and effective method of administering topical anesthesia before shave biopsy in adult patients.