Benzocaine spray products may cause life-threatening condition

The commonly-used anesthetic benzocaine may inhibit red blood cells’ capacity to carry oxygen, which in some cases can result in cyanosis and life-threatening complications. An article in the June 14, 2004 issue of Archives of Internal Medicine, authored by the Institute for Safe Medication Practices (ISMP), analyzes adverse event reports regarding benzocaine products that have been submitted to the U.S. Food and Drug Administration.

According to ISMP, most recently reported cases of benzocaine-induced methoglobinemia (MHb), which is characterized by abnormal levels of oxidized hemoglobin that cannot bind or transport oxygen, have occurred in the hospital setting in connection with intubation, endoscopic, or bronchoscope procedures. Prior to those procedures, a spray dosage form of benzocaine is often used to anesthetize the patient’s oropharynx and suppress the gag reflex.

Administering a correct dose of benzocaine is difficult since listed doses range from 0.5 second to 1 second sprays, and variations in the amount dispensed may occur due to canister position and amount of remaining contents.

SOURCE: Press release, Institute for Safe Medication Practices, July 21, 2004.