Methemoglobinemia may occur in patients who overdose with acetaminophen (paracetamol), although this may be overshadowed by the toxic hepatitis.
Patient selection: overdose of acetaminophen
The exposure may be suicidal or an accidental therapeutic overdosage.
Risk factors for methemoglobinemia:
(1) G6PD deficiency
Clinical presentation:
(1) altered mentation
(2) cyanosis
(3) multi-organ failure
(4) discoloration of the blood (dark brown)
The ingestion may be complicated by the presence of other ingested drugs or chemicals.
Therapy may include a combination of:
(1) N-acetyl cysteine (NAC)
(2) hemodialysis
(3) methylene blue
(4) ascorbic acid
