Administration of NaNO<sub>2</sub> alone increased methemoglobin levels and methemoglobin reductase activity, decreased the activities of antioxidant defense and metabolic enzymes and significantly weakened the total antioxidant capacity of rat erythrocytes.
We present a case of unusually severe methemoglobinemia (82% methemoglobin) secondary to occupational exposure that failed to respond to several lines of management including methylene blue, red cell exchange, intravenous ascorbic acid, and hyperbaric oxygen.