Topical Transdermally Delivered Lidocaine and Benzocaine Compared to Compounded Lidocaine/Tetracaine During Microfocused Ultrasound With Visualization Treatment
July 2018 | Volume 17 | Issue 7 | Original Article | 729 | Copyright © July 2018
Melanie D. Palm MD MBA,a Lisa M. Misell PhDb
aArt of Skin MD, Solana Beach, CA bDyve Biosciences, Thousand Oaks, CA
Abstract
Objective: The efficacy of various pre-medication strategies for comfort management during microfocused ultrasound with visualization
(MFU-V) treatment has not been studied. The present objective was to compare 2 topical analgesics (lidocaine 4% and benzocaine
20%) formulated with a novel transdermal delivery system with compounded lidocaine 23%/tetracaine 7% (23/7) to mitigate discomfort
during MFU-V treatment.
Methods: This was a randomized, double-blinded, split-face study. One hour before MFU-V, subjects (N=14 females) received 50 mg
IM meperidine/25 mg IM promethazine/5 mg oral diazepam. Fifteen minutes before treatment, 1 side of the face was treated with 1
application of 4% lidocaine, followed by 1 application of 20% benzocaine; the contralateral side was treated with 2 applications of 23/7
(to maintain blinding). Numbness was assessed by blinded evaluator (scale: 1=completely numb to 4=not numb) pre-treatment. Subject
pain scores (scale: 0=no pain to 10=worst pain) were collected post-treatment. Adverse events and subjective clinician measures
were also assessed.
Results: Mean subject pain scores for 23/7 and lidocaine 4%/benzocaine 20% were 5.6 and 5.7, respectively. Mean numbness scores
were similar for 23/7 (2.5) and lidocaine 4%/benzocaine 20% (3.0). Clinicians rated both products as “very easy†to apply. For lidocaine
4%/benzocaine 20%, 7.1% of subjects required no pauses during treatment, vs 14.3% for 23/7. However, more subjects required 4+
pauses with 23/7 (21.4% vs 7.1%). Lidocaine 4%/benzocaine 20% was preferred by 78.5% of subjects; 35.7% rated lidocaine/benzocaine
20% 4% as “Very Effective†vs 7.1% for 23/7. No adverse events were reported.
Conclusions: Lidocaine 4% and benzocaine 20% formulations utilizing a novel transdermal delivery system perform similarly to compounded
lidocaine 23%/tetracaine 7% for discomfort mitigation during MFU-V treatment. More subjects preferred lidocaine 4%/
benzocaine 20% and rated it as “very effective†vs the compounded product. Fewer treatment pauses due to patient discomfort when
using the lidocaine 4%/benzocaine 20% may translate to time efficiency.
J Drugs Dermatol. 2018;17(7):729-734.
INTRODUCTION
Interest in minimally invasive cosmetic procedures is increasing,1 with patients pursuing the use of fillers for volume loss, peels, and laser treatments for photoaging, and energy-based devices for skin tightening and lifting lax tissue to improve contours and reduce the appearance of wrinkles and fine lines. Microfocused ultrasound with visualization (MFU-V; Ultherapy; Merz North America, Inc., Raleigh, NC) has been shown to be a safe and effective nonsurgical treatment for skin laxity.2-6 MFU-V is currently cleared by the United States Food and Drug Administration (FDA) for lifting and tightening skin on the neck, chin, and brow, as well as for improving lines and wrinkles on the chest.7In the pivotal clinical studies supporting FDA clearance of MFU-V, a range of oral and topical agents were administered before treatment for comfort management, with somewhat variable results on patient-reported pain scores (using 11-point scales). In the pivotal study for the neck and submentum, scores ranged from 5.7–6.5 depending on the area treated,3 and in the study on the brow and periorbital region, scores were 3–4 on average.2 When MFU-V was used for rejuvenation of the chest, pain scores were 4.8–6.2, depending on which transducer was used (with transducers targeting deeper tissue associated with higher pain scores).4 Overall, the comparative efficacy of various premedication strategies for comfort management during MFU-V treatment has not been systematically examined using controlled studies.Because MFU-V is able to treat layers of the skin up to 4.5 mm deep,7 it is expected that systemic agents and fast-acting topical treatments that are able to penetrate deeply may be most effective for comfort management during treatment. However, there remains a clinical need for FDA-approved topical analgesics that are fast-acting and reach deeper into the tissue. Frequently
