What's New in Topical Anesthesia

https://doi.org/10.1016/j.cpem.2007.08.002Get rights and content

Advances in topical anesthesia have brought new products, new drug delivery systems, and new indications. Eutectic mixture of local anesthetics, LMX4, and Synera are available for skin anesthesia before minor skin-breaking procedures such as venipuncture and intravenous cannulation. Several systems to enhance drug delivery, shortening onset of skin anesthesia to 5 minutes or less, are commercially available. These include iontophoresis, pretreatment of skin with laser or ultrasound, and needle-free jet injection of local anesthetics. Protocols for placing topical anesthetics at triage also reduce negative impact on emergency department flow. Despite these advances, topical anesthetics are not routinely used in emergency departments for minor procedures. This article reviews available and upcoming topical anesthetic products, as well as adverse effects, and procedure and disease-specific uses of topical anesthesia.

Section snippets

Topical Anesthetics for Intact Skin

Eutectic mixture of local anesthetics (EMLA) (AstraZeneca Pharmaceuticals LP, Wilmington, DE) is an oil-in-water emulsion of 2.5% prilocaine and 2.5% lidocaine that was approved by the Food and Drug Administration (FDA) in 1992. It is particularly useful on intact skin before superficial skin-breaking procedures such as venipuncture, intravenous (IV) catheter placement, implanted venous catheter access, vaccination, and intramuscular injection, etc. Eutectic mixture of local anesthetics (EMLA)

Methods to Reduce the Time-to-Effect Barrier

Iontophoresis takes advantage of the polarization of lidocaine and uses low-level electric current to enhance transdermal delivery, usually of a lidocaine and epinephrine solution [31]. Several systems are commercially available, including Numby Stuff (Iomed Inc, Salt Lake City, UT), LidoSite (B. Braun Medical Inc, Bethlehem, PA), and Iontophor (Life-Tech Inc, Stafford, TX). Iontophoresis results in skin anesthesia to a greater depth than EMLA (10 vs 5 mm with EMLA), is comparable to or better

Topical Anesthetics for Laceration Repair

TAC (tetracaine 0.5%, adrenalin or epinephrine 0.05%, and cocaine 11.8%) was first studied over 25 years ago [2]. Application of TAC solution to an open wound for 20 to 30 minutes resulted in equivalent analgesia to local infiltration of lidocaine, particularly for scalp and face wounds 49, 50. Emergency department use peaked in the 1990s [51]. However, accidental mucous membrane exposure may result in severe central nervous system and cardiac toxicity because of the cocaine component,

Needle-Free Options

There are several needle-free options to achieve subcutaneous administration of local anesthetic, which compete with topical anesthetics as pain management solutions for minor skin-breaking procedures. A needle-free jet injection system, J-tip (National Medical Products, Inc, Irvine, CA), uses a carbon dioxide gas source to force up to 0.25 mL of medication at a time subcutaneously via high velocity jet injection. It has been used successfully to administer buffered 1% or 2% lidocaine local

Adverse Effects of Topical Anesthetics

Methemoglobinemia is a potential serious adverse effect of topical anesthetics, particularly in infants. The highest risk patients are preterm neonates and infants less than 3 months old [65]. Although both lidocaine and prilocaine are oxidants that promote formation of methemoglobin, significant methemoglobinemia has been reported with use of EMLA (thought to be due primarily to the prilocaine component) and benzocaine topical anesthesia 66, 67. Methemoglobinemia presents hours after exposure

Procedure-Specific Applications for Topical Anesthetics

Eutectic mixture of local anesthetics, LMX4, Ametop, Synera, lidocaine iontophoresis, and needle-free jet injection of lidocaine are all options for pain reduction before venous access procedures such as venipuncture and IV cannulation. To avoid time spent waiting for topical anesthetic effect and a negative impact on ED flow, topical anesthetics may be placed on patients thought to likely require a venous access procedure in triage or placed immediately upon physician's order of the procedure.

Disease-Specific Applications for Topical Anesthetics

Topical benzocaine solutions, such as Auralgan (14% benzocaine; Wyeth Pharmaceuticals, Madison, NJ) relieve the pain of otitis media but are indicated only when the clinician is sure that there is no tympanic membrane perforation [88]. Viral stomatitis is commonly treated with “magic mouthwash” made up of equal parts of diphenhydramine, Maalox, and viscous lidocaine, although no studies exist to lend support to this practice [89]. Teething pain is also commonly treated with over-the-counter

Summary

Advances in topical anesthesia have brought improved products and drug delivery devices that reduce the time to effect. Although EMLA requires 45 to 60 minutes for effect, LMX4 and Synera are effective within 20 to 30 minutes. Placement at triage reduces the negative impact on ED flow. New commercially available devices can reduce the time to effect further to 5 minutes or less. Despite these advances, topical anesthetics are not being routinely used for minor skin-breaking procedures in EDs; a

References (94)

  • S. Priestley et al.

    Application of topical local anesthetic at triage reduces treatment time for children with lacerations: a randomized controlled trial

    Ann Emerg Med

    (2003)
  • S.A. Grant et al.

    Use of tetracaine, epinephrine, and cocaine as a topical anesthetic in the emergency department

    Ann Emerg Med

    (1992)
  • M. Tripp et al.

    TAC toxicity in the emergency department

    Ann Emerg Med

    (1991)
  • A. Eidelman et al.

    Comparative efficacy and costs of various topical anesthetics for repair of dermal lacerations: a systematic review of randomized, controlled trials

    J Clin Anesth

    (2005)
  • K. Resch et al.

    Topical anesthesia for pediatric lacerations: a randomized trial of lidocaine-epinephrine-tetracaine solution versus gel

    Ann Emerg Med

    (1998)
  • W.T. Zempsky et al.

    EMLA versus TAC for topical anesthesia of extremity wounds in children

    Ann Emerg Med

    (1997)
  • I.H. Hahn et al.

    EMLA-induced methemoglobinemia and systemic topical anesthetic toxicity

    J Emerg Med

    (2004)
  • L.L. Gerard et al.

    Effectiveness of lidocaine lubricant for discomfort during pediatric urethral catheterization

    J Urol

    (2003)
  • L. Cullen et al.

    Nebulized lidocaine decreases the discomfort of nasogastric tube insertion: a randomized, double-blind trial

    Ann Emerg Med

    (2004)
  • J. Ducharme et al.

    What is the best topical anesthetic for nasogastric insertion? A comparison of lidocaine gel, lidocaine spray, and atomized cocaine

    J Emerg Nurs

    (2003)
  • T.R. Wolfe et al.

    Atomized lidocaine as topical anesthesia for nasogastric tube placement: a randomized, double-blind, placebo-controlled trial

    Ann Emerg Med

    (2000)
  • G.N. Russell et al.

    Local anesthesia for radial artery cannulation: a comparison of a lidocaine-prilocaine emulsion and lidocaine infiltration

    J Cardiothorac Anesth

    (1988)
  • W.T. Zempsky et al.

    Office-based pain management. The 15-minute consultation

    Pediatr Clin North Am

    (2000)
  • G.M. Ehrenstrom Reiz et al.

    EMLA—a eutectic mixture of local anaesthetics for topical anaesthesia

    Acta Anaesthesiol Scand

    (1982)
  • G. Kaur et al.

    A randomized trial of eutectic mixture of local anesthetics during lumbar puncture in newborns

    Arch Pediatr Adolesc Med

    (2003)
  • L.M. Joly et al.

    Topical lidocaine-prilocaine cream (EMLA) versus local infiltration anesthesia for radial artery cannulation

    Anesth Analg

    (1998)
  • J. Browne et al.

    The use of EMLA reduces the pain associated with digital ring block for ingrowing toenail correction

    Eur J Anaesthesiol

    (2000)
  • J. Lander et al.

    Comparison of ring block, dorsal penile nerve block, and topical anesthesia for neonatal circumcision: a randomized controlled trial

    JAMA

    (1997)
  • G. Ehrenstrom-Reiz et al.

    Topical anaesthesia with EMLA, a new lidocaine-prilocaine cream and the Cusum technique for detection of minimal application time

    Acta Anaesthesiol Scand

    (1983)
  • M. Calamandrei et al.

    Comparison of two application techniques of EMLA and pain assessment in pediatric oncology patients

    Reg Anesth

    (1996)
  • A.B. Acharya et al.

    Randomised controlled trial of eutectic mixture of local anaesthetics cream for venipuncture in healthy preterm infants

    Arch Dis Child Fetal Neonatal Ed

    (1998)
  • C.M. Essink-Tebbes et al.

    Safety of lidocaine-prilocaine cream application four times a day in premature neonates: a pilot study

    Eur J Pediatr

    (1999)
  • J.L. Koh et al.

    Efficacy of parental application of eutectic mixture of local anesthetics for intravenous insertion

    Pediatrics

    (1999)
  • J.A. Lander et al.

    EMLA and amethocaine for reduction of children's pain associated with needle insertion

    Cochrane Database Syst Rev

    (2006)
  • T.S. Shomaker et al.

    Evaluating skin anesthesia after administration of a local anesthetic system consisting of an S-Caine patch and a controlled heat-aided drug delivery (CHADD) patch in volunteers

    Clin J Pain

    (2000)
  • B. Berman et al.

    Self-warming lidocaine/tetracaine patch effectively and safely induces local anesthesia during minor dermatologic procedures

    Dermatol Surg

    (2005)
  • N.F. Sethna et al.

    A randomized controlled trial to evaluate S-Caine patch for reducing pain associated with vascular access in children

    Anesthesiology

    (2005)
  • H.A. Bryan et al.

    The S-Caine peel: a novel topical anesthetic for cutaneous laser surgery

    Dermatol Surg

    (2002)
  • J.Z. Chen et al.

    Evaluation of the S-Caine Peel for induction of local anesthesia for laser-assisted tattoo removal: randomized, double-blind, placebo-controlled, multicenter study

    Dermatol Surg

    (2005)
  • J. Lander et al.

    Evaluation of a new topical anesthetic agent: a pilot study

    Nurs Res

    (1996)
  • P.M. Friedman et al.

    Comparative study of the efficacy of four topical anesthetics

    Dermatol Surg

    (1999)
  • P.M. Friedman et al.

    Topical anesthetics update: EMLA and beyond

    Dermatol Surg

    (2001)
  • S.C. Zappa et al.

    Use of ethyl chloride topical anesthetic to reduce procedural pain in pediatric oncology patients

    Cancer Nurs

    (1992)
  • S. Mawhorter et al.

    Topical vapocoolant quickly and effectively reduces vaccine-associated pain: results of a randomized, single-blinded, placebo-controlled study

    J Travel Med

    (2004)
  • C. Ramsook et al.

    Efficacy of ethyl chloride as a local anesthetic for venipuncture and intravenous cannula insertion in a pediatric emergency department

    Pediatr Emerg Care

    (2001)
  • M. Costello et al.

    Ethyl vinyl chloride vapocoolant spray fails to decrease pain associated with intravenous cannulation in children

    Clin Pediatr (Phila)

    (2006)
  • E.H. Davies et al.

    Comparison of ethyl chloride spray with topical anaesthetic in children experiencing venepuncture

    Paediatr Nurs

    (2006)
  • Cited by (19)

    • Behavioural alterations in piglets after surgical castration: Effects of analgesia and anaesthesia

      2019, Research in Veterinary Science
      Citation Excerpt :

      This suggestion arises from comparison of behavioural changes between piglets castrated with and without pain-relief medications. On the other hand, Young (2007) suggested that local anaesthesia could be effective in mitigating inflammatory pain caused by open wounds in young children. Similar to the efficacy of NSAIDs, it can therefore be speculated that administration of local anaesthetics might be more effective for relieving mid- to long-term pain related to inflammation induced by an incisional wound, rather than acute pain after castration.

    • The Power of Topical Anesthetics and Distraction for Peripheral Intravenous Catheter Placement in the Pediatric Perianesthesia Area

      2018, Journal of Perianesthesia Nursing
      Citation Excerpt :

      This device is easy to use, results of anesthesia are quick, and this tool is cost-effective. The cost for a Lidocaine J-tip is slightly less than that of LMX4 and EMLA at $1.50 per device.8 A drawback of the Lidocaine J-tip is the sudden “popping” noise that is created when the carbon dioxide is released.

    • The use of an iced cotton bud as an effective pre-cooling method for palatal anaesthesia: A technical note

      2017, Singapore Dental Journal
      Citation Excerpt :

      In contrast, the buccal mucosa is not as tightly bound and as anaesthesia is delivered the tissue expands with the volume of anaesthesia injected, thus less pain is felt by the patient. The use of topical anaesthetics to reduce pain during the delivery of intra oral anaesthesia have been ongoing since the 1980s [3]. In addition to topical anaesthesia, pressure application or ice application to the site are practiced to reduce the pain from tissue expansion in the palatal region.

    View all citing articles on Scopus
    View full text