DAPSONE INDUCED METHEMOGLOBINEMIA: CASE REPORT

Naveen Kumar, Aiswarya Wilson, Aalia P.S, Dr. Hari Lakshmanan and Dr. Aneesa S herif

ABSTRACT

Dapsone, a sulfone compound widely used for various dermatological and infectious conditions, is associated with adverse effects such as Heinz body hemolytic anemia and methemoglobinemia. Methemoglobinemia is a rare but potentially life-threatening condition where hemoglobin is oxidized to methemoglobin, impairing oxygen delivery and leading to hypoxia. We report two cases of dapsone-induced methemoglobinemia who presented with persistent hypoxia without an alternate etiology. Both patients exhibited a characteristic "saturation gap" (low SpO₂ with normal PaO₂ in arterial blood gas analysis). Given their history of prolonged dapsone use, the drug was discontinued, following which showed significant improvement in oxygen saturation confirming the diagnosis. Dapsone-induced methemoglobinemia should be considered in patients with unexplained hypoxia, especially when a saturation gap is observed. Early identification and discontinuation of dapsone are crucial for preventing severe complications. A high index of suspicion and close monitoring patients on dapsone therapy is key to early diagnosis.

Keywords: Dapsone, Methemoglobinemia, Hypoxia, Saturation gap.