will reduce the pain of subsequent administration of lidocaine by injection The gel can be applied directly to the wound and allowed to remain for approximately 20 to 30 minutes, the solution can be “painted” onto the wound with a cotton-tipped swab, or a saturated cotton ball can be applied to the wound and held in place manually or with tape There may be a temporary stinging sensation when first applied Subsequently, the surrounding skin will be well blanched, indicating adequate local anesthesia Like lidocaine with epinephrine, the classic teaching advises that LET should not be applied to body parts where vasoconstriction is contraindicated, however some studies have questioned this One study found no cases of digit ischemia in patients with topical lidocaineadrenaline-tetracaine (LAT) applied to simple lacerations LET has essentially replaced tetracaine, adrenaline, cocaine (TAC) compound as the preferred topical anesthetic for wound repair because it is much less costly and has reduced toxicity TAC carries the risk of cocaine toxicity and can lead to seizures and death, especially if used near mucous membranes where rapid absorption can occur Topical Anesthetics for IV Placement and Venipuncture There are many products available for topical anesthesia through intact skin and these have been found helpful in relieving pain associated with IV catheter placement and venipuncture in children Decisions about IV line placement can often be made at triage, thus allowing topical agents time to take effect If preparing for IV line placement, one should prepare multiple sites in case the first attempt is unsuccessful, which occurs between 50% and 75% of the time, depending on whether or not the child is dehydrated These products are also useful for drainage of an abscess or paronychia, arthrocentesis, lumbar puncture, or to access implantable central venous catheters All topical anesthetics currently available contain lidocaine either alone or mixed with another anesthetic Mechanisms of delivery and onset times are variable The delivery mechanism must traverse the stratum corneum, which contains highly ordered lipid bilayers that block the entry or exit of water or water-soluble substances Products can traverse this barrier using needleless injection with pressurized gas, passive diffusion, or by interrupting or bypassing the barrier using heat, ultrasound, or electricity