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Acquired methemoglobinemia from multiple oxidants
J M Conroy1, J D Baker, W J Martin
1Department of Anesthesiology, Medical University of South Carolina, Charleston 29425.
Southern Medical Journal
|October 1, 1993
Summary
Phenazopyridine can cause methemoglobinemia, especially with overdose or kidney issues. This case highlights that even normal doses, combined with other drugs like lidocaine, can overload erythrocyte reductase pathways, leading to this condition.
Area of Science:
- Toxicology
- Pharmacology
- Hematology
Background:
- Phenazopyridine is a urinary tract analgesic.
- Methemoglobinemia is a condition where hemoglobin is oxidized, reducing oxygen transport.
- Risk factors for phenazopyridine-induced methemoglobinemia include overdose, renal dysfunction, and genetic predisposition (e.g., NADH methemoglobin reductase deficiency).
Observation:
- A patient developed methemoglobinemia despite receiving a normal dose of phenazopyridine.
- The patient had no evident renal dysfunction and a history of prior uneventful phenazopyridine use.
- The patient was also administered lidocaine and bupivacaine concurrently.
Findings:
- Methemoglobinemia in this case was attributed to metabolic overload of erythrocyte reductase pathways by multiple oxidants, specifically phenazopyridine and lidocaine.
- Bupivacaine was not implicated in the development of methemoglobinemia.
- The study suggests considering chemotherapy-induced enzyme pathway alterations in similar cases, although direct links are sparsely studied.
Implications:
- This case expands the understanding of phenazopyridine-induced methemoglobinemia beyond typical risk factors.
- Concurrent administration of multiple oxidant drugs can precipitate methemoglobinemia even in the absence of overdose or renal impairment.
- Further research into drug interactions and chemotherapy effects on metabolic pathways is warranted.