Comparative study between two topical anesthetics in dermatological procedures

Received on: 14/01/2018

Approved on: 04/03/2018

Study conducted at Dermoclínica – Dermatologia e Laser, Campinas – SP, Brazil.

Financial support: None

Conflict of interests: None

Abstract

Introduction: Managing pain during the performance of dermatological procedures is a challenge. Several topical anesthetics are available for use prior to carrying out minimally invasive treatments.
Objective: To evaluate the efficacy of topical anesthetics for reducing the pain during dermatological procedures and to compare the effectiveness of two different anesthetics using the visual numeric pain scale.
Methods: Twenty-five patients underwent facial dermatological procedures after the application of two commercial preparations: one containing 7% lidocaine and 7% tetracaine (applied in one hemiface) and the other containing 4% lidocaine. Each of the preparations was applied in one hemiface. Pain intensity was assessed using the Visual Numeric Pain Scale (VNS) at the end of the procedure.
Results: Eighty-four percent of the patients reported a lower pain score in the hemiface that received the commercial preparation containing 7% lidocaine and 7% tetracaine. The mean pain score in the hemifaces that received the 4% lidocaine preparation was 7.3, while that computed for the hemifaces that received the 7% lidocaine and 7% tetracaine preparation was 5.3.
Conclusions: Topical anesthetics are effective and safe for pain reduction in dermatological procedures, with the commercial preparation containing 7% lidocaine and 7% tetracaine was more effective than the one containing 4% lidocaine.

Keywords: Anesthesia; Anesthesia, local; Dermatologic surgical procedures; Minimally invasive surgical procedures; Pain perception; Pretreatment

INTRODUCTION

The increased demand for aesthetic dermatological procedures is remarkable; however, one of their challenges is pain. This lead to an increased need for the use of effective and safe topical anesthetics, providing more comfort for the patient and guaranteeing better results.^1,2 There are many topical anesthetics available in the Brazilian market, such as commercial preparations of 2.5% lidocaine and 2.5% prilocaine (Emla^® AstraZeneca do Brasil Ltda, São Paulo, Brazil),³ commercial preparation of 4% lidocaine (Dermomax^® Aché laboratórios farmacêuticos, São Paulo, Brazil)⁴ and commercial preparation of 7% lidocaine and 7% tetracaine (Pliaglis^® Galderma Brasil Ltda, São Paulo, Brazil).⁵ The objective of this study was to compare the efficacy between two topical anesthetics, the commercial preparation of 4% lidocaine (Dermomax^®) and the commercial preparation of 7% lidocaine and 7% tetracaine (Pliaglis^®), evaluating pain scores in patients undergoing different types of dermatological procedures.

METHODS

Prospective and comparative pilot study, in the same patient.

Twenty-five patients from a private practice in Campinas (SP) were submitted to different dermatological procedures – fractional CO₂ laser (SmartXide^®, Deka Medical Lasers, Florence, Italy), intense pulsed light (all wavelengths – Harmony XL^®, LBT Lasers, São Paulo, Brazil), infrared (Cutera xeo^®,Titan^® tip, California, USA), radiofrequency (Reaction^®, Viora Medical Solutions, Israel), q-switched laser for the removal of pigmented from the eyebrows and intradermal injection of hyaluronic acid.

All patients were female, aged between 25 and 71 years (mean of 48,6 years). Thirty minutes before the procedure, a thick layer of the commercial preparation containing 4% lidocaine (Dermomax^® Aché laboratórios farmacêuticos, São Paulo, Brazil) was applied to one side of the face, chosen randomly, and on the other side the commercial preparation of 7% lidocaine and 7% tetracaine (Pliaglis^® Galderma Brasil Ltda, São Paulo, Brazil) was applied. The study was blind for the patients. The parameters used in each procedure were the same for both sides of the face. Pain intensity was evaluated by the Visual Numeric Pain Scale (VNS) at the end of the procedure ( Figure 1), considering zero absence of pain and 10, maximum pain.^6,7

The ethical guidelines from the declaration of Helsinki were adopted in this study.

RESULTS

Eighty percent (20/25) of the patients reported better analgesia on the side where the commercial preparation of 7% lidocaine and 7% tetracaine was applied; 12% (3/25) of the patients reported similar pain scores; and 8% (2/25) reported slightly less pain on the side of the face pre-treated with 4% lidocaine, as shown in table 1.

The mean score of the side of the face where the commercial preparation of 4% lidocaine (Dermomax^®) was applied was of 7.4, while the mean of the side of the face where the commercial preparation of 7% lidocaine and 7% tetracaine (Piaglis^®) was applied was of 5.3, as shown in table 2.

The two patients who reported equal values on the pain scale (patients 12 and 24, according to Table 1) reported high scores in the pain scale, respectively 8 and 9 on a scale with maximum pain of 10. Also, in relation to the comparison between both anesthetics, there were cases like patients 15 and 22, who reported a large difference regarding the evaluation of analgesia when comparing both sides of the face ( Table 1). We would also like to call attention to patient 16, who reported maximum pain (score 10) during fractional CO₂ laser on the side of the face where lidocaine was applied and 7.5 on the other side, where the anesthetic containing lidocaine in higher concentration associated to tetracaine was applied, what allows us to infer an important effect in analgesia provided by the product containing the combination of anesthetics. Only two patients reported more pain on the side of the face where the commercial preparation of 7% lidocaine and tetracaine was applied, however, we should mention that the difference observed was small compared to the side of the face where the anesthetic containing 4% lidocaine was applied (patients 11 and 18, 1 point difference).

There were no significant side effects.

DISCUSSION

Pain is still a limiting factor for many dermatological procedures. With the advent of topical anesthetics, these procedures became more reasonable in clinical practice without the need of resorting to infiltrative anesthesia, blocks or sedation.^1,2,8

Topical anesthetics are effective and safe for many dermatological procedures, such as ablative and non-ablative lasers, injection of fillers and botulinum toxin, radiofrequency, infrared and intense pulsed light, with a low risk for adverse events.^8-10

These agents act in dermal nerve endings, reducing the transmission of afferent nerve impulses.^11,12 The topical anesthetic interacts with sodium channels in the nerve endings, blocking their influx. The threshold of excitation increases and gradually reduces the action potential onset and conduction of the nerve impulse. However, for that to occur, local anesthetics should propagate through the stratum corneum and reach the interior of nerve fibers. Ability of propagation, anesthetic potency, pharmacokinetics characteristics and adverse events are intrinsically related to their chemical structure and physical-chemical properties.^1,2,9,10,12

Even though pain is a subjective symptom, difficult to measure, the Visual Numeric Pain Scale (VNS) is already considered a good parameter for the quantification of pain and is widely used in many areas of medicine.^6,7

This study compared the efficacy in the control of pain of two topical anesthetics: a commercial preparation of 7% lidocaine and 7% tetracaine and a commercial preparation of 4% lidocaine. Pain scores were lower for most patients pre-treated with the commercial preparation of 7% lidocaine and 7% tetracaine (20 patients – 80%) and higher in patients pre-treated with the commercial preparation of 4% lidocaine.

The first commercial preparation evaluated was more effective in 80% of 25 patients participating in this study, in relation to the pain reported during a dermatological procedure, indicated in the Visual Numeric Pain Scale ( Figure 1); with a two-point difference when compared to the other formulation containing only 4% lidocaine. Three patients reported similar scores for both products. It is also worth highlighting that for the only two patients who reported higher pain with the association of lidocaine and tetracaine, the difference was small when compared to the side where only 4% lidocaine was used.

CONCLUSION

It was possible to observe in this study that the cream with 7% lidocaine and 7% tetracaine was more effective in most patients assessed, with more effective analgesia of the face during different dermatological treatment than the product containing 4% lidocaine.

DECLARATION OF PARTICIPATION:

Sandra Tagliolatto | ORCID 0000-0003-2203-0692
Data collection, text review and submission of the article.

Gabriela Nero Mitsuushi | ORCID 0000-0003-1941-525x
Bibliographical review and preparation of the manuscript.

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