<p><strong>Symptoms</strong>: nausea, vomiting, hyperexcitability (within a few min to up to 24 hr later), methemoglobin-induced depression, haemolysis (7-14 days after ingestion), seizures and severe cyanosis.<br />
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<strong>Treatment</strong>: activated charcoal (20g four times daily) and haemolysis may enhance elimination of dapsone and its monoacetyl derivative. For patients without G6PD deficiency, methemoglobinemia may be treated with methylene blue 1-2 mg/kg given by slow IV injection (repeated if methemoglobin reaccumulates) or in less severe cases, 3-5 mg/kg every 4-6 hr orally.</p>