Dapsone Induced Methemoglobinemia: The Importance of Early Diagnosis

We present a case of a 65-year-old male with lower respiratory tract infection who developed methemoglobinemia after starting dapsone therapy. The patient presented with cyanosis and dyspnea, and arterial blood gas analysis revealed a methemoglobin level of 14%. Dapsone was discontinued, and the patient was treated with methylene blue and Vitamin C IV infusion, which resulted in rapid improvement of symptoms and normalisation of methemoglobin levels. This case highlights the importance of recognizing dapsone-induced methemoglobinemia early and promptly initiating appropriate treatment to prevent complications.