ALERTA FDA: Productos para disminuir dolor en tejidos de superficie por estudios mamográficos y otros destinos diagnósticos

FDA Public Health Advisory
Potential Hazards of Skin Products Containing Numbing Ingredients for Relieving Pain from Mammography and Other Medical Tests and Conditions



FDA is issuing this advisory to remind patients, healthcare professionals, and caregivers about potentially serious hazards of using skin numbing products, also known as topical anesthetics, for relieving pain from medical tests and conditions. In February 2007, FDA issued a Public Health Advisory- Life-Threatening Side Effects with the use of Skin Products Containing Numbing Ingredients for Cosmetic Procedures -that described the deaths of two young women who used topical anesthetics prior to laser hair removal [http://www.fda.gov/cder/drug/advisory/topical_anesthetics.htm]. Now, FDA is aware that lidocaine, a type of topical anesthetic, was studied to see if it may reduce discomfort during breast mammography1.

During the study, the topical product was spread over a wide area and covered with plastic wrap. Although no serious side-effects were reported in this study, it was not large enough to evaluate whether uncommon but serious reactions could occur with this use. FDA remains concerned about the potential for topical anesthetics to cause serious and life-threatening adverse effects when applied to a large area of skin or when the area of application is covered.

Topical anesthetics work by blocking pain sensation in the skin. Some of the medication in a topical anesthetic can pass through the skin into the blood stream. More of the medication will pass into the blood stream if the topical anesthetic is applied over a large area of the skin, if a large amount is applied, if it is applied to irritated or broken skin, or if the skin temperature increases. Skin temperature can increase during exercise, by covering the skin with a wrap, or with use of a heating pad. Under these circumstances, the amount of anesthetic medication that reaches the blood stream is unpredictable and may be high enough to cause life-threatening adverse effects such as irregular heartbeat, seizures, breathing difficulties, coma and even death.

There are several topical anesthetics available by prescription and over-the-counter. When used appropriately, these products may provide safe and effective pain relief. Before recommending a topical anesthetic for any purpose, doctors should determine if the desired amount of pain relief can be achieved safely with a topical anesthetic, or if a different treatment would be more appropriate. If a topical anesthetic is determined to be the best choice, the lowest needed amount should be prescribed. Patients should speak with their doctor if they are considering using a topical anesthetic before a mammogram. If a topical anesthetic is recommended then patients should:

use a topical anesthetic that contains the lowest amount possible of medication that will relieve the pain;
apply the topical anesthetic sparingly and only to the area where pain exists or is expected to occur;
not apply the topical anesthetic to broken or irritated skin.
ask their doctor what side effects are possible and how to lower their chance of having life-threatening side effects from anesthetic drugs.
be aware that if wrapping or covering the skin with any type of material or dressing is recommended or considered, this can increase the chance of serious side effects, as can applying heat to the treated area while the medication is still present.
FDA is working with healthcare professional organizations and other media that distribute healthcare information to spread the message about the potential hazards and safe use of topical anesthetics.


1Lambertz CK et al. Premedication to Reduce Discomfort during Screening Mammography. Radiology 2008; 248 (3): 765-72.
Stakeholder Letter(PDF)
Date created: January 16, 2009