Benzocaine is a topical anesthetic frequently used in healthcare facilities and in over-the-counter medications in concentrations up to 20%. Benzocaine may induce methemoglobinemia, a condition that impairs the blood’s ability to carry oxygen. The optimal management of exposure to benzocaine remains unclear because serious toxicity is uncommon and may not be dose-related. In 2000, it was estima...

Case. We report a case of severe methemoglobinemia due to sodium nitrite poisoning. A 28-year-old man was brought to our emergency department because of transient loss of consciousness and cyanosis. He was immediately intubated and ventilated with 100% oxygen. A blood test revealed a methemoglobin level of 92.5%. Outcome. We treated the patient with gastric lavage, activated charcoal, and methy...

A 27-year-old man who had 2 admissions 1 month apart for abdominal surgery had a high methemoglobin (MHb) level secondary to liberal use of benzocaine oral spray. A co-oximetry level for MHb of greater than 0.30 proportion of total hemoglobin (30.1%) was detected intraoperatively. The patient was successfully treated with methylene blue intravenously and recovered uneventfully. When the arteria...

Acquired methemoglobinemia is a medical emergency, and its prompt recognition and treatment can avoid catastrophic complications including death. However, in mild asymptomatic cases without any comorbid conditions, it would be reasonable to simply observe and treat symptomatically to avoid severe treatment-related complications, especially in patients with suspected glucose-6-phosphate dehydrog...

Experiments by one of us (1) have shown that methemoglobinemia exerts a protective effect in dogs against poisoning due to inhalation of HCN and CNCl. The possibility of applying these findings in man raised the question as to the extent to which methemoglobinemia would impair various physiological functions. Several groups of investigators (2 to 4) have found that a rise in the threshold of th...

Methemoglobin is a type of hemoglobin in which the ferrous ion has been oxidized to the ferric state. It is therefore incapable of combining with or transporting the oxygen molecule, which is replaced by a hydroxyl radical. Methemoglobinemia can be acquired or inherited. Most cases are acquired and are primarily due to exposure to certain drugs and chemicals, such as nitrates, nitrites, quinone...

The electrophoretic mobility and activity of NADH-methemoglobin reductase in erythrocytes of patients with hereditary methemoglobinemia, obligatory heterozygotes, and normal subjects were examined. Six distinct electrophoretic variants were found in studies of erythrocytes from members of ten different families. Five variants (Boston Slow, Duarte, Princeton, Puerto Rico, and California) were as...

To the Editor: A recent letter in this journal described methemoglobinemia and hemolysis due to rasburicase in a patient with glucose-6-phosphate dehydrogenase (G6PD) deficiency [1]. We would like to report on the management of a patient with rasburicase induced methemoglobinemia and G6PD deficiency. DS is a 12-year-old Laotian male who presented with a white blood cell count of 533,900/mm (89%...

cyanosis develops in the absence of any car. diac or respiratory abnormalities.1 Cyanosis is a result of the accumulation of methemoglobin, which imparts a bluish color to the blood. This condition has two forms: a hereditary and an acquired form. Hereditary methemoglobinemia is an extremely rare inborn error of metabolism resulting in the accumulation of methemoglobin. 2 The acquired form resu...