What's New in 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
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Cited by (19)
Behavioural alterations in piglets after surgical castration: Effects of analgesia and anaesthesia
2019, Research in Veterinary ScienceCitation 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 NursingCitation 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 JournalCitation 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.