Methemoglobinemia caused by benzocaine topical spray.

Acute methemoglobinemia is a medical emergency that can rapidly become fatal. A substantial number of drugs, including topical preparations, can precipitate this condition. I report a rare example of severe, acute methemoglobinemia caused by oropharyngeal anesthesia with topical benzocaine spray for orogastric intubation. The pathophysiology, diagnosis, and treatment of methemoglobinemia are reviewed briefly.