Methemoglobinemia: A Rare Entity Caused by Commonly Used Topical Anesthetic Agents, a Case Report

Benzocaine, a topical anesthetic agent, is widely used during short procedures like endoscopy, endotracheal intubation and likewise. Here we report a case of benzocaine spray-induced methemoglobinemia in an adult male patient during the transesophageal echocardiography (TEE) presenting as hypoxia and improved subsequently in the next 2 h on low-dose intravenous methylene blue. Causality assessment of the adverse event was probable, and preventability assessment was unpreventable. The patient was discharged with no further complications at good health. A relevant etiopathology and managing principles are summarized in this case report such that it serves as an awareness to all medical fraternity about this unexpected yet life-threatening adverse drug reaction to an otherwise safe local anesthetic.