We all know about the tremendous advantages that local anesthetic agents have made in the field of surgery and dermatology. Inguinal hernia repairs, carpal tunnel releases, eyelid surgery, nose-lift surgery, etc are performed every day as outpatient procedures and without the need of a general anesthetic agent. Lidocaine is perhaps the most common local anesthetic used throughout the world. It has a wide safety margin and many medical practitioners use it and other local anesthetics, quite possibly without really thinking that they may have systemic consequences to patients.
Aside from local anesthetics that are injected into the skin, topical anesthetics are also widely used to numb the skin for medical and cosmetic procedures, and provide analgesia for pain, burning, or itching associated with various medical conditions. Some topical anesthetics require a prescription, while others are available over-the-counter (OTC).
The United States Food and Drug Administration (FDA) has issued an advisory regarding the risk of serious adverse effects with the use of topical anesthetics. Since some of these products can be obtained over-the-counter (OTC), their indiscriminate use may occur as a result of inadequate advice and supervision by trained health care professionals. Without this supervision, a patient may apply large amounts of topical anesthetics to their skin. When overly applied, high blood levels may result that cause life threatening adverse effects, including arrhythmias, seizures, or death.
The “safety” comfort level provided by local anesthetics can sometimes be misleading and may result in situations complicated by its use. Take for example, two cases reported to the FDA following topical anesthetic use --- two women aged 22 and 25 years old, applied topical anesthetics to their legs to lessen pain during laser hair removal. These women then wrapped their legs in plastic wrap, as they were instructed, to increase the cream’s numbing effect. Both women had seizures, resulting in comas, and subsequently died from the toxic effects of the anesthetic drugs. The skin numbing creams used in these two cases were made in pharmacies and contained high amounts of the anesthetic drugs lidocaine and tetracaine.
Unfortunately, these are not the first patients to die from the extensive use of topical anesthesia. This is also similar to complications experienced in plastic surgery of deaths associated with large volume liposuctions, fluid overload and toxicity from tumescent infusion of lidocaine solution. These cases bring to fore, the importance of having procedures performed by board-certified medical professionals who have had extensive training in their sub-specialties to include pharmacologic toxicity awareness and prevention. It also helps to check for appropriate accreditation of the facility to ensure that patient safety policies are implemented and that life-saving equipment is in place.
In cases where larger quantities of local anesthetics are used, its important for physicians to describe the early symptoms of overdose to patients, and instruct them to notify the physician if they experience any of these effects.
Examples of topical anesthetic agents include benzocaine (Americaine, Cetacaine), dibucaine (Nupercainal), lidocaine (Xylocaine, Lidoderm), tetracaine (Pontocaine), Pramoxine (Caladryl Cream for Kids), and lidocaine/prilocaine (EMLA).
In summary, even though local anesthetic agents are a major factor in the success of the outpatient surgery revolution, physicians must be knowledgeable in patient safety practices and in the prevention and management of local anesthetic toxicity. This consideration must now extend to the topical agents used to prepare patients for procedures as well.