Acute methaemoglobinaemia after massive nitrobenzene ingestion.

Flower-N is a flowering stimulant composition with 22% nitrobenzene. The main systemic effect associated with human exposure to nitrobenzene is methaemoglobinaemia. A 25-year-old female presented after 3 hours following ingestion of 100 ml of 22% Nitrobenzene (Flower-N). Her initial methaemoglobin (MetHb) was 81%; this responded to methylene blue. However, she developed recurrent methaemoglobinaemia on days 3 and 5 with haemolytic anaemia. The treatments that were provided were repeated methylene blue treatment and exchange transfusion. Nitrobenzene ingestion is a known cause of methaemoglobinaemia and haemolytic anaemia. The recurrence suggests a long half-life. The recurrent MetHb has clinical implications as patients may require repeated treatment. Massive nitrobenzene ingestion can cause haemolysis and recurrent methaemoglobinaemia.