Acute dapsone intoxication: a case treated with continuous infusion of methylene blue, forced diuresis and plasma exchange.

A case of massive dapsone poisoning (15 g) in a 26 year old man is reported. The patient exhibited high plasma dapsone concentration, marked methemoglobinemia, and signs of hemolysis. He recovered completely after intensive treatment with methylene blue, activated charcoal, forced diuresis, and plasma exchange. In order to avoid overdosage of methylene blue it is concluded that this substance should be given by continuous intravenous infusion in cases with severe methemoglobinemia. This way of administration caused a steady decrease in the methemoglobin concentration compared to intermittent administration. Plasma exchange was of minor benefit, probably due to the large distribution volume of dapsone.