Perioperative Hypoxia Secondary to Phenazopyridine-induced Methemoglobinemia in an Adolescent Patient Without Renal Insufficiency or Overdose: An Unusual Case.

Phenazopyridine is a common, well-tolerated medication with minimal side effects. Severe side effects are rare and include methemoglobinemia in setting of overdose, elderly patients, renal insufficiency, and chronic use. Here, we report a case of methemoglobinemia-induced perioperative hypoxia in an adolescent patient without renal insufficiency or overdose which has not been reported previously. This case underscores the importance of judicious use of this medication in all patients but notably in pediatric patients and those with chronic lung disease.