Minor procedures can have serious adverse effects. The article by Chowdhary et al quantitates a serious but rare adverse effect, namely, methemoglobinemia associated with the use of topical oropharyngeal anesthetics for invasive procedures. The studies for which the topical anesthetics are used are common procedures that are typically thought to be safe, such as transesophageal echocardiography and upper gastrointestinal tract endoscopy. The association of methemoglobinemia with topical anesthetics cannot be eliminated, although it was less common when the anesthetics did not contain benzocaine. However, before any procedure is performed, even one we think of as very safe, we can ensure that the benefits outweigh the risks.
Katz MH. Serious Adverse Effects Can Occur With Minor ProceduresComment on “Risk of Topical Anesthetic–Induced Methemoglobinemia”. JAMA Intern Med. 2013;173(9):776. doi:10.1001/jamainternmed.2013.93