Topical anesthetics are drugs applied to the skin to block pain and itching. They target the nerve endings in the dermis and mucosa and cause a temporary loss of sensation in a limited area. Topical anesthetics may be in the form of liquid or gel. Most are available without a prescription, but physicians may prescribe specific formulations and doses for patients with specific medical conditions.
One of the most common applications of topical anesthetics is the treatment of lacerated wounds. The application of topical anesthetics not only relieves the pain from these wounds but also prevents the risk of accidental needle sticks. This is especially helpful for children who often have stronger reactions to needles. However, topical anesthetics have some disadvantages as well. A common example is the long waiting time between the time patients arrive at the emergency room and the time it takes for the plastic surgeon to close their wound.
Tetracaine is a topical anesthetic that can be used to provide pain relief during certain procedures. It is usually combined with lidocaine and applied to intact skin 20 to 60 minutes before the procedure. However, tetracaine can have systemic side effects. This can include cardiovascular and CNS toxicity. Regardless of the type of procedure, Tetracaine should only be used with the knowledge and expertise of a qualified healthcare professional.
Cryogen sprays have a variety of uses, including anesthesia and cryosurgery. They can reduce the surface temperature of human skin to as low as -30 degC. This cooling is useful because it promotes rapid and spatially selective epidermis cooling. Spraying cryogen on human skin reduces the surface temperature to below -30 degC while leaving the basal layer unaffected.
The most common cryogen is liquid nitrogen. Before liquid nitrogen was available, physicians used compressed carbon dioxide, snow, or liquid air as cryogens. The method is now mostly replaced by liquid nitrogen sprays because of their ease of use. Cryogen sprays can be applied to both benign and malignant lesions.
Ice topical anesthesia is a method used to reduce pain during dental procedures. Its effect is apparent as early as one minute after application. It is cheap and easily available. However, it has certain limitations. Ice does not have a long-lasting analgesic effect and may not be appropriate for all patients. The pharmacological component used in ice should be avoided due to the risk of allergic reactions.