Benzocaine Sprays, Gels and Liquids: Increased Risk of Methemoglobinemia - Update
April 8, 2011
FDA is alerting healthcare professionals and consumers that benzocaine sprays used in medical procedures and benzocaine gels and liquids applied to the gums and mouth for pain relief may cause methemoglobinemia. Methemoglobinemia is a rare condition that reduces the amount of oxygen carried in the blood. The most serious cases can result in death. Methemoglobinemia presentation includes skin, lips, or nail bed discoloration; shortness of breath; lightheadedness; fatigue; confusion; headache; or rapid heart rate. The signs and symptoms usually occur within minutes to a few hours after application and may occur after one or more uses. If any of these symptoms occur after using benzocaine, stop use and seek medical attention.
FDA issued a warning in 2006 concerning risk of methemoglobinemia associated with the use of benzocaine spray prior to medical procedures after receiving nearly 250 adverse event reports. Since that time, FDA has received 72 additional reports of methemoglobinemia associated with benzocaine spray, three of which resulted in death. FDA also received 21 reports of methemoglobinemia associated with use of over-the-counter benzocaine gels or liquids. Most of the reported events occurred in children two years of age and younger treated with benzocaine gels for teething pain. FDA found that methemoglobinemia can occur following a single dose of any of the marketed benzocaine spray, gel, or liquid products as well as with excessive use. Methemoglobinemia occurred with all strengths of benzocaine gels and liquids as well as benzocaine sprays used to numb the mouth or throat prior to bronchoscopy, intubation, feeding tube placement, or similar procedure.
Current labeling for benzocaine products does not contain methemoglobinemia warnings. FDA will continue to evaluate the risk of methemoglobinemia associated with benzocaine products and provide updated information or regulatory changes as necessary. Consumers should follow labeled recommendations for use of benzocaine products, using the smallest amount possible and not exceeding 4 applications per day. Do not use benzocaine products in children under 2 years of age unless recommended by a physician. The American Academy of Pediatrics recommends giving children a chilled teething ring as well as softly rubbing or massaging the child’s gums for teething pain relief. FDA recommends healthcare professionals familiarize themselves with the signs and symptoms of methemoglobinemia. When recommending benzocaine products, advise patients to monitor for signs and symptoms of methemoglobinemia. Patients with underlying breathing problems, heart disease, and patients who smoke are at greater risk for methemoglobinemia.
Additional information is available at the following links:
- MedWatch Alert (April 7, 2011):
- MedWatch Alert (February 13, 2006):
- Drug Safety Communication (Benzocaine Liquids and Gels):
- Drug Safety Communication (Benzocaine Sprays):
April 8, 2011, University of Utah, Drug Information Service. Copyright 2011, Drug Information Service, University of Utah, Salt Lake City, UT.