Acute Poisoning with Dapsone and Olanzapine: Severe Methemoglobinemia and Coma with a Favourable Outcome

Dapsone is a drug commonly used in the treatment of leprosy. In Europe it is rarely prescribed, mostly for the treatment of skin diseases such as dermatitis herpetiformis. Poisoning with dapsone is rare and reports of such cases are of interest for toxicological practice. We describe the only acute dapsone poisoning in a caseload series of 21,000 intoxications treated in the Clinical Toxicology Clinic at St George University Hospital in Plovdiv, Bulgaria between 1999 and 2013. We report on a 36-year-old woman who attempted deliberate self-poisoning with an ingestion of approximately 4.5 g of dapsone and 0.3 g of olanzapine. On admission, the patient was in a state of severe intoxication and comatose. On admission to hospital 9 hours after the ingestion, the methemoglobin level was 51.7%. The patient recovered 8 days later. She received complex treatment including intubation, ventilation, repeated gastric lavage, hemodialysis, blood exchange transfusion and antidote treatment with methylene blue. She was discharged in good clinical condition with minimal organ damage such as mild toxic hepatitis.