title: Benzocaine-induced methemoglobinemia: experience from a high-volume transesophageal echocardiography laboratory.
abstract: Benzocaine (ethyl aminobenzoate), a topical anesthetic widely used before transesophageal echocardiography, has been reported to cause acquired methemoglobinemia. The incidence of benzocaine-induced methemoglobinemia in clinical practice, however, has been difficult to estimate. After systematic review of our institutional experience for clinically recognized cases of benzocaine-induced methemoglobinemia in patients undergoing transesophageal echocardiography, we report an estimated incidence of 0.115% (95% confidence interval 0.037-0.269). This report also provides the largest analysis of the incidence of methemoglobinemia in readministration cases. Although controversy remains as to whether this is an idiosyncratic versus dose-related response, a description of purported patient risk factors is included.
authors.affiliation: Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, OH 44195, USA.
authors.forename: Gian M
authors.initials: GM
authors.lastname: Novaro
authors.forename: Herbert D
authors.initials: HD
authors.lastname: Aronow
authors.forename: Michael A
authors.initials: MA
authors.lastname: Militello
authors.forename: Mario J
authors.initials: MJ
authors.lastname: Garcia
authors.forename: Ellen Mayer
authors.initials: EM
authors.lastname: Sabik
mesh_terms: D000328:Adult; D000368:Aged; D001566:Benzocaine / Q000009:adverse effects; D017548:Echocardiography, Transesophageal; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008708:Methemoglobinemia / Q000139:chemically induced / Q000000981:diagnostic imaging / Q000453:epidemiology*; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D001566:Benzocaine