Phenazopyridine-Induced Methemoglobinemia: A Case Report

Methemoglobinemia is a condition caused by increased methemoglobin, a reduced form of hemoglobin, in the blood. This causes the molecules to bind oxygen more tightly and decreases their ability to release that oxygen to tissue. Most cases of methemoglobinemia are acquired and occur either in pediatric populations or in individuals with predisposing conditions. This report illustrates a case of an otherwise healthy 31-yearold patient presenting to the emergency department with cyanosis of the hands and mouth and an O2 saturation of 78% after taking increased doses of the over-the-counter medication phenazopyridine. A ???chocolate-brown??? color of her arterial blood, and increased methemoglobin levels of 20.2%, confirmed the diagnosis of methemoglobinemia. She was treated with both methylene blue and ascorbic acid, and her oxygen saturation and serum chemistry returned to normal levels within a few hours. The case highlights the importance of discussing the dosage of all over-the-counter medications with patients and recognizing the signs and symptoms of methemoglobinemia.

Automated summary

This case presents a healthy 31-year-old patient who developed Methemoglobinemia after taking excessive doses of the over-the-counter medication phenazopyridine. The patient showed severe cyanosis and a "chocolate-brown" color of arterial blood, with confirmed methemoglobin levels. Prompt treatment with methylene blue and ascorbic acid resulted in a successful recovery. This case emphasizes the importance of discussing medication dosage with patients and recognizing the signs and symptoms of Methemoglobinemia.