phenazopyridine

Although toxicity with phenazopyridine is relatively uncommon, when it does occur, it may present with a varied and potentially serious clinical picture.

Phenazopyridine 2010

The blue color of methylene blue may impart a transitory cyanosis to the patient which clears as the methylene blue is converted to the active and colorless leukomethylene blue. 1 It is theoretically possible that repeat doses may be required in phenazopyridine ingestions due to persistent and prolonged production of toxic metabolites.

Phenazopyridine 2010

In the case presented, the only symptom of phenazopyridine toxicity observed was cyanosis with profound methemoglobinemia.

Phenazopyridine 2010

Acute haemolytic anaemia due to phenazopyridine hydrochloride in G-6-PD deficiency subject.

Phenazopyridine 2010

Rarely have patients with normal renal function developed acute renal failure. 13,16 Renal toxicity due to phenazopyridine may be a direct effect of the drug and/or its metabolites, or may be secondary to hypoxic injury when methemoglobinemia occurs. 13 Treatment is usually supportive.

Phenazopyridine 2010

Because neonates have both an immature NADH-dependent methemoglobin reductase system and higher levels of fetal hemoglobin,11-12 they are more susceptible to the oxidative stresses which can be seen with phenazopyridine.

Phenazopyridine 2010

The mechanism for hemolytic anemia with phenazopyridine use has not been described.

Phenazopyridine 2010

Transient acute oliguric13,14 or nonoliguric15,16 renal failure may be seen with large doses13,15,16 or prolonged use14 of phenazopyridine.

Phenazopyridine 2010

Methemoglobinemia is a serious complication which can occur with acute phenazopyridine ingestions.

Phenazopyridine 2010

Hemolytic anemia has been reported with chronic therapeutic use2-6 and with acute overdoses7 of phenazopyridine and may be the only sign of toxicity.

Phenazopyridine 2010