The need for caution with topical anesthesia during endoscopic procedures, as liberal use may result in methemoglobinemia

J Clin Gastroenterol. 2004 Mar;38(3):225-9. doi: 10.1097/00004836-200403000-00006.


During upper gastrointestinal endoscopy, topical oropharyngeal anesthesia with lidocaine and/or benzocaine is used routinely by many endodscopists. Although such a practice is usually safe, there have been a number of reports of methemoglobinemia induced by topical anesthesia. Early treatment is extremely important as the development of methemoglobinemia is potentially fatal. Methemoglobinemia should be considered when oxygen desaturation occurs without another explanation. In this case series, we report 4 cases of methemoglobinemia that followed the liberal application of Cetacaine for ERCP. All patients recovered after appropriate treatment but these cases serve to highlight the potential problem, the importance of early recognition and treatment, and the most appropriate treatment options.

Publication types

  • Case Reports

MeSH terms

  • 4-Aminobenzoic Acid / adverse effects*
  • Administration, Topical
  • Aged
  • Anesthetics, Local / adverse effects*
  • Benzalkonium Compounds / adverse effects*
  • Benzocaine / adverse effects*
  • Cetrimonium Compounds / adverse effects*
  • Cholangiopancreatography, Endoscopic Retrograde / methods*
  • Drug Combinations
  • Female
  • Humans
  • Male
  • Methemoglobinemia / chemically induced*
  • Methemoglobinemia / diagnosis
  • Methemoglobinemia / therapy
  • Middle Aged
  • Tetracaine / adverse effects*
  • para-Aminobenzoates*


  • Anesthetics, Local
  • Benzalkonium Compounds
  • Cetrimonium Compounds
  • Drug Combinations
  • benzocaine, butyl aminobenzoate, tetracaine drug combination
  • para-Aminobenzoates
  • Tetracaine
  • 4-Aminobenzoic Acid
  • Benzocaine