Methemoglobinemia in children with acute lymphoblastic leukemia (ALL) receiving dapsone for pneumocystis carinii pneumonia (PCP) prophylaxis: A correlation with cytochrome b5 reductase (Cb5R) enzyme levels

BACKGROUND: Dapsone is commonly used for pneumocystis carinii pneumonia (PCP) prophylaxis in immunocompromised patients. Methemoglobinemia is a known complication of dapsone, but its true frequency and pathogenesis in childhood cancer patients are unknown. Additionally, practice guidelines for evaluation and management of dapsone-induced methemoglobinemia are not available. PROCEDURE: We studied 15 children with acute lymphoblastic leukemia …