Methemoglobinemia caused by topical benzocaine.

Benzocaine-induced methemoglobinemia is a rare but life-threatening event. The use of topical benzocaine spray in a 77-year-old woman during endoscopic retrograde cholangiopancreatogram produced marked cyanosis and methemoglobin levels consistent with methemoglobinemia. Immediate recognition and prompt treatment of the disorder are essential to decrease morbidity and mortality.