Guidance on the treatment of lacerations and wounds supports the use of topical local anesthetics to provide analgesia and facilitate wound repair. The Wilderness Medical Society 2024 guideline identifies LET (lidocaine/epinephrine/tetracaine) and EMLA (lidocaine/prilocaine) as topical anesthetic formulations with demonstrated efficacy and safety for wounds and laceration repair and recommends topical or locally instilled local anesthetics for soft-tissue injuries. The Royal Children’s Hospital Melbourne (RCH) guideline specifically recommends ALA (adrenaline/lidocaine/tetracaine) gel (Laceraine®) applied directly to the wound and identifies EMLA (lidocaine/prilocaine) and AnGel® (tetracaine 4%) as suitable alternatives. However, Laceraine® and AnGel® are not marketed in the U.S. The American Academy of Family Physicians (AAFP) similarly identifies LET and lidocaine/prilocaine as commonly used topical anesthetics for laceration repair. For lidocaine/prilocaine, the AAFP lists its use in patients older than 3 months for nonintact skin and at any age for intact skin, while noting it is not FDA-approved for use on nonintact skin despite having been used in numerous studies. [1], [2], [3]
A 2022 meta-analysis aimed to evaluate the efficacy of topical anesthetics in pediatric wound management. A comprehensive literature search across five databases identified eight eligible studies for review that utilized lidocaine-prilocaine (EMLA) and lidocaine-epinephrine-tetracaine (LET) for pain reduction. The meta-analysis revealed that LET significantly reduced pain compared to control interventions (standardized mean difference [SMD] -0.46; 95% confidence interval [CI] -0.69 to -0.23; p<0.0001; 3 studies), while a eutectic mixture of local anesthetics (EMLA) did not show a statistically significant difference in pain reduction (SMD -0.79; 95% CI -1.82 to -0.24; p= 0.13; 3 studies). The incidence of adverse events (AEs) was minimal and was not significantly different between LET (odds ratio [OR] 0.99; 95% CI 0.15 to 6.50; p= 0.99) and EMLA (OR 2.31; 95% CI 0.67 to 7.93; p= 0.18). These findings suggest that LET may be effective in reducing pain during pediatric wound management, with minimal AEs, while EMLA’s efficacy is less conclusive. [4]
A 2017 Cochrane review evaluated the efficacy and safety of topical anesthetics for pain control during the repair of dermal lacerations. The review included 25 randomized controlled trials (RCTs) with a total of 3,278 participants, comprising both pediatric and adult populations. Various topical anesthetic formulations, both cocaine-containing (epinephrine-cocaine, cocaine, bupivacaine-epinephrine-cocaine, tetracaine-epinephrine-cocaine, tetracaine-cocaine) and cocaine-free (anesthetic putty containing 4.94% w/w lidocaine hydrochloride, bupivacaine-norepinephrine, EMLA, etidocaine-norepinephrine, lidocaine-epinephrine-tetracaine, lidocaine-epinephrine, mepivacaine-norepinephrine, prilocaine-norepinephrine, prilocaine-phenylephrine, tetracaine, tetracaine-epinephrine, tetracaine-lidocaine-phenylephrine, and tetracaine-phenylephrine) were compared against each other and against infiltrated local anesthetics. According to the findings, several cocaine-free topical anesthetics demonstrated comparable analgesic efficacy to cocaine-containing formulations, suggesting that the inclusion of cocaine may not be clinically necessary. In two pooled studies, prilocaine-phenylephrine resulted in slightly higher visual analog scale (VAS) pain scores compared to tetracaine-epinephrine-cocaine, with a mean difference of 5.59 (95% confidence interval [CI] -2.16 to 13.35). Despite concerns regarding the risk of adverse effects with topical anesthetics, the review reported no serious complications across the included studies, with only one mild erythematous reaction observed. However, the overall quality of evidence was deemed low due to design limitations, imprecision, and a high risk of bias in several trials. The findings underscore the need for additional well-designed RCTs to further evaluate the optimal topical anesthetic regimen for dermal laceration repair. [5]
A 2017 review discusses the goals of laceration repair to achieve homeostasis and optimal cosmetic results without increasing the risk of infection. Topical and injectable local anesthetics such as epinephrine may reduce pain during the treatment of these lacerations and may be used alone or in combination. Local injection with epinephrine at a concentration of up to 1:100,000 is safe for use on digits, and concentrations of 1:200,000 are safe for use on the nose and ears. Additionally, although lidocaine/prilocaine (EMLA) cream is not approved by the Food and Drug Administration for use on nonintact skin, it has been effectively utilized for pain management during laceration repair in various studies. Thus, lidocaine/prilocaine cream may be a viable anesthetic alternative in combination with proper irrigation techniques, such as use of sterile gloves and appropriate suturing methods, in effective anesthesia and wound management. [6]
A 2011 systematic review compared the effectiveness of topical hemostatic agents for donor site wounds following split-thickness skin grafting (SSG) using nine randomized controlled trials encompassing 376 donor sites in 340 predominantly burn patients. Various hemostatic agents, including epinephrine, fibrin sealant, thrombin, alginate dressings, saline, and mineral oil, were compared. Data indicated that epinephrine achieved hemostasis significantly faster than thrombin, saline, or mineral oil, reducing time to hemostasis by up to 6.5 minutes, whereas fibrin sealant demonstrated superiority over thrombin by approximately one minute. A 2011 trial included in the review reported no notable adverse effects for epinephrine or fibrin sealant, while costs were inadequately assessed across studies. Another 1996 trial demonstrated that epinephrine in K-Y jelly or spray form significantly decreased hemostasis time compared to controls. A 2003 randomized trial found fibrin sealant reduced time to hemostasis relative to thrombin. However, despite these findings, the absence of direct comparisons between epinephrine and fibrin sealant leaves uncertainty regarding the optimal choice. The review concluded that epinephrine and fibrin sealant appear most effective for minimizing topical blood loss in SSG donor sites, but these results are not applicable to laceration wounds. [7]
A 2021 systematic review discusses topical anesthetics for use in pain management of dermal injuries. The most prominently cited option is EMLA cream, a pre-formulated eutectic mixture of 2.5% lidocaine and 2.5% prilocaine, which has demonstrated efficacy for procedures like suturing and wound debridement. Other straightforward alternatives include various single-agent lidocaine formulations, such as 4% or 5% lidocaine available in ready-to-use gel, liquid, or patch formats (e.g., lidocaine patch). A tetracaine 1% solution is another single-agent option, though the evidence notes it may be less effective for certain applications like corneal abrasions. These pre-made options provide effective topical anesthesia, simplifying the clinical workflow by eliminating the need for compounding while maintaining patient comfort and safety. [8]
In general, if preparing LET gel from a compounding kit, reconstitution of a conventionally manufactured nonsterile product is to be considered nonsterile. Per USP <795>, preparations which are utilized in body spaces which don’t freely “communicate” or have contact with the environment outside of the body (e.g., bladder cavity) are required to be sterile, as well as ophthalmic products and compounded aqueous inhalation solutions and suspensions. Otic preparations; irrigations for the mouth, rectal cavity, and sinus cavity; and nasal sprays are not required to be sterile. Based on these examples, LET preparations are not required to be sterile; however, some manufacturers (e.g., Fagron and Quva) specifically label their ready-to-use LET topical gel preparations as having either gone through filtration sterilization or prepared with sterile active pharmaceutical ingredients (API). [9], [10], [11]