[Methemoglobinemia caused by accidental poisoning with metolachlor and metobromuron]

An 81-year-old man was admitted in the emergency department approximately four hours after accidental, ingestion of an unknown quantity of herbicide "Galex 500 EC". This product contains 25% of metolachlor and 25% of metobromuron dissolved in xylene. In spite of the fact that the combination of aniline and urea-substituted derivatives is widely used in agriculture as herbicide, there are very few data available about their harmful effects on humans. These agents appear to be mildly toxic, and rarely has a major systemic effect been reported after the poisoning. On admittance, our patient showed remarkable cyanosis and his methaemoglobin level was 38.4% of the total haemoglobin, rising next day to 46.2%. Only mild transient signs of hypoxic effects on central nervous system were observed and the laboratory findings indicated mild haemolysis. Methylene blue was applied intravenously in a dose of 1.5 mg/kg (10 ml, 1% solution) on the second day of admission. Administration of methylene blue was very effective and the patient was discharged from the hospital fully recovered.