Acquired methemoglobinemia from phenazopyridine use

Abstract

BackgroundPhenazopyridine-induced methemoglobinemia is relatively rare with fewer than ten cases reported over the past 35 years. We describe a case of phenazopyridine-induced methemoglobinemia that is unique in the way the patient presented and how initial workup was completed.Case presentationThe patient presented with lethargy, diarrhea, light-headedness, and headaches, with past medical history of breast cancer, seizures, and recent dysuria for which she had been taking phenazopyridine. She was noted to have a persistent hypoxemia despite supplemental oxygen delivery and a shunting process was considered, with pulmonary embolus and methemoglobinemia due to phenazopyridine use being of chief concern. She was stabilized, and confirmation of original diagnosis was made at the main ED and treatment successfully rendered with good effect.ConclusionsMethemoglobinemia, while rare, can be associated with use of over-the-counter medicines and should be considered as part of a broad differential. This case serves to emphasize the importance of a thorough history and physical—tools especially helpful when at a satellite facility with relatively limited resources.

Phenazopyridine-Induced Methaemoglobinaemia - The Aftermath of Dysuria Treatment

“…In the case of phenazopyridine poisoning, this cascade is circumvented, resulting in methaemoglobin build-up. Other medications that have been associated with acquired methaemoglobinaemia are local anesthetic agents and dapsone [ 3 ] .…”

A Case of Severe Hypoxia Caused by Phenazopyridine-Induced Methemoglobinemia: A near Fatal Event from Over-the-Counter Medication Use

“…Phenazopyridine is a known cause of acquired methemoglobinemia. However, only a handful of cases have been reported in the literature in the last twenty years, summarized in ( Table 3 ) [ 5 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. The various patient factors such as chronic kidney disease, heart and lung disease, anemia, and inherent enzymes such as G6PD deficiency, Cytochrome b5 reductase (Cyb5R) deficiency, or heterozygotes variant with a lower than average baseline activity increase susceptibility for phenazopyridine-induced methemoglobinemia [ 16 ].…”

Approaches to pain management in urology

“…Метгемоглобинемия бывает врожденной и приобретенной. Приобретенная метгемоглобинемия развивается в результате действия на организм некоторых лекарств, промышленных и экотоксикантов, которые либо непосредственно окисляют железо, входящее в структуру гемоглобина, либо метаболизируют в организме с образованием реактивных продуктов, обладающих этим свойством [17]. Индуцированная феназопиридином метгемоглобинемия встречается относительно редко, и за последние 35 лет в мире было зарегистрировано менее 10 случаев заболевания [17].…”