June 2006, Volume 36 Number 6 , p 64hn7 - 64hn7
Benzocaine sprays such as Hurricaine, Topex, and Cetacaine may be applied to a patient's mouth and throat to numb his mucous membranes before a procedure, such as insertion of an endotracheal or gastric tube. Incorrect use of these sprays, such as spraying longer or more frequently than recommended, has led to cases of methemoglobinemia. In this rare adverse reaction, excess methemoglobin in red blood cells prevents iron in hemoglobin from binding oxygen and carrying it to the body tissues. Signs and symptoms range from headache to cyanosis, indicating hypoxia.