Methemoglobinemia due to ingestion of at most three pills of pyridium in a 2-year-old: case report and review.

Pyridium (phenazopyridine HCl) is a commonly prescribed medication in the treatment of urinary tract infections and is known to cause methemoglobinemia in excessive doses. We report the case of a 2-year-old child who ingested a maximum of three 200-mg tablets (approximately 50 mg/kg) of pyridium and yet developed cyanosis and methemoglobinemia (29.1%), resulting in methylene blue therapy. We urge physicians to consider a period of observation (4-6 h) or to obtain methemoglobin levels in children who ingest even a small number of pyridium tablets because this can represent a toxic dose in a small child.