Phenazopyridine should be used with caution especially for an infant younger than 1 month or with G6PD deficiency because of the risk for methemoglobinemia, sulfhemoglobinemia
, and hemolytic anemia.
This may be due to hypoxemia, methemoglobinemia, or sulfhemoglobinemia
The use certain drugs such as sulfonamides are associated with the development of sulfhemoglobinemia
Peripheral cyanosis may be caused by pulmonary, cardiac and vascular diseases, enzyme deficiency, methemoglobinemia, sulfhemoglobinemia
, and hemoglobin anomalies.
Hemoglobin oxidation: methemoglobin, methemoglobinemia, and sulfhemoglobinemia
As a result, a congenital methemoglobinemia attributable to HbM may be mistakenly diagnosed as carbon monoxide poisoning or toxic sulfhemoglobinemia
, as happened with this patient (despite her acknowledgement of a family history of chronic methemoglobinemia at presentation).
1] recently described a case of sulfhemoglobinemia