Oral Nitrate Induced Methemoglobinemia and Hemolysis: A Rare Case Report

Acquired methemoglobinemia is a clinical condition precipitated by some offending agents, like nitrates. We are reporting a case of methemoglobinemia with hemolysis in a 51-year-old adult patient after oral nitrate use. The patient was a case of inferior wall myocardial infarction with complete heart block post-stenting to the right coronary artery. Two days later, the patient started desaturating with normal partial pressure of oxygen in arterial blood and fraction of inspired oxygen, along with signs of hemolysis. After reviewing medications, oral nitrate was thought to be the offending agent, which was withdrawn. Oxygen supplementation with a high dose of vitamin C and other supportive care was given. Due to the unavailability of a confirmatory test, serum methemoglobin was sent to an outside laboratory and came back positive after a few days. The patient responded to the treatment and was discharged after 10 days. By presenting this case, we aim to raise awareness about the potential risks of oral nitrates and the importance of early diagnosis and intervention.