Isoniazid (INH) is a bactericidal antituberculosis agent. Overdose of isoniazid is characterized by seizures, metabolic acidosis, and coma. It can result in death if untreated.Parenteral pyridoxine administration is an effective method in INH intoxication. The intravenous form of pyridoxine must be available in the emergency care units, and INH toxicity should be suspected in any patient with refractory seizures and metabolic acidosis.