title: Benzocaine-associated methemoglobinemia following bronchoscopy in a healthy research participant.
abstract: Benzocaine (ethyl aminobenzoate) is a local anesthetic commonly used to achieve topical anesthesia of the skin and mucous membranes prior to endoscopic procedures. Methemoglobinemia, a condition in which hemoglobin cannot bind and deliver oxygen normally, has been associated with benzocaine use in various patient populations. This is the first report of benzocaine-associated methemoglobinemia occurring in a healthy research participant. The research participant developed a methemoglobin level of 27% and marked cyanosis. No adverse sequelae other than cyanosis were identified. This report extends the population in which benzocaine-associated methemoglobinemia has been described. Additionally, this report supports the observation that methemoglobin levels approaching 30% may be tolerated in otherwise healthy individuals, producing few clinically important effects. Finally, this case also indicates that, in obtaining informed consent for a procedure in which benzocaine will be administered, patients and research participants should be specifically informed of the risk of benzocaine-induced methemoglobinemia. This information is especially important in those settings in which the manufacturer-recommended dose of benzocaine may either intentionally or inadvertently be exceeded.
authors.affiliation: Veterans Affairs Palo Alto Health Care System, and the Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, California, USA. kuschner@stanford.edu
authors.forename: W G
authors.initials: WG
authors.lastname: Kuschner
authors.forename: R K
authors.initials: RK
authors.lastname: Chitkara
authors.forename: J
authors.initials: J
authors.lastname: Canfield
authors.forename: L M
authors.initials: LM
authors.lastname: Poblete-Coleman
authors.forename: B A
authors.initials: BA
authors.lastname: Cunningham
authors.forename: P S
authors.initials: PS
authors.lastname: Sarinas
mesh_terms: D000287:Administration, Topical; D000368:Aged; D000779:Anesthetics, Local / Q000009:adverse effects*; D001566:Benzocaine / Q000009:adverse effects*; D001999:Bronchoscopy; D006801:Humans; D007258:Informed Consent; D008297:Male; D008708:Methemoglobinemia / Q000139:chemically induced*; D009960:Oropharynx
chemical_list: D000779:Anesthetics, Local; D001566:Benzocaine