Methanol is highly toxic to humans. Although methanol poisoning is not uncommon in developing countries, poisoning caused by ingestion of commercial products containing undeclared methanol has rarely been reported. Herein, we describe two patients who experienced methanol poisoning after ingestion of liquid rodenticides. A 39-year-old woman attempted suicide by ingesting liquid rodenticide which contained bromadiolone. She developed high anion gap metabolic acidosis and coagulopathy. Methanol poisoning was confirmed 20 hours later. She received oral ethanol therapy and hemodialysis. Vitamin K1 was also administered. She did not develop any hemorrhage or visual impairment and was discharged after 11 days. The rodenticide sample was tested and found to have a methanol concentration of 324 g/L. In another case, a 62-year-old man ingested the same brand of rodenticide. Laboratory data showed mild metabolic acidosis with an increased osmol gap, suggestive of methanol poisoning. He received hemodialysis and eventually recovered without sequelae. Liquid rodenticide may contain methanol as a solvent. Ingestion of a methanol-containing commercial product without a clear label can result in a considerable delay in diagnosis and management. Methanol poisoning should be considered for patients who present with unexplained metabolic acidosis following exposure to liquid rodenticides or other liquid commercial products.
Keywords: anticoagulant; methanol poisoning; rodenticide; solvent; vitamin K antagonist.