Topical Anesthetics Linked to Serious Injury and Death: FDA Warns

The FDA has issued a Public Health Advisory about potential side effects of topical anesthetics, or skin number products, which are available over-the-counter (OTC) or as a prescription to relieve pain from mammography and other medical tests. Improper use of the topical anesthetic creams, ointments or gels could cause serious and potentially life-threatening side effects.

Topical anesthetics, such as lidocaine gel, are absorbed through the skin into the bloodstream, desensitizing nerve endings near the surface of the skin to produce a numbing effect.

In a letter sent to healthcare providers and a notice posted on their website, the FDA indicates that they are concerned that women may improperly use the topical anesthetics prior to mammography by applying too much of the gel or ointment, applying the products to a large area of skin, applying it directly to irritated or broken skin, covering the skin or using a heating pad after application.

“Improper use of topical anesthetics can lead to excessive absorption of the drug into the bloodstream and may cause life-threatening side effects such as irregular heartbeat, seizures, breathing difficulties, coma and even death,” wrote Teresa Toigo, the FDA’s Director of the Office of Special Health Issues, in a letter dated January 16, 2009.

Reports of problems with topical anesthetics have been received by the FDA, including at least two women who died after using the skin numbing products before laser hair removal.

The FDA has recommended that if an over-the-counter or prescription topical anesthetic is recommended, consumers should use the lowest amounts of the medication necessary to relieve pain. Doctors have also been asked to consider whether a different treatment would be more appropriate if pain can not be relieved without excessive use of a topical anesthetic.

Applying too much of the topical anesthetic, or wrapping or covering to the area of skin treated could increase the risk of side effects of the skin numbing products. As the skin temperature increases, the amount of anesthetic that reaches the bloodstream could increase.

A recent study published in the medical journal Radiology looked at the use of oral pain relievers compared to the use of the topical anesthetic lidocain gel to decrease discomfort during mammography and no serious or life-threatening side effects were identified.

Although the researchers indicated that use of lidocain gel resulted in less discomfort than acetaminophen or ibuprofen, the FDA suggests that because of the two known topical anesthetic deaths associated with use during laser hair removal, similar side effects could occur when it is used during mammography.