Acute isoniazid intoxication: reversal of CNS symptoms with large doses of pyridoxine.

Acute toxicity from ingestion of isoniazid (INH) is manifested by coma and seizures unresponsive to conventional therapy. Though small doses of pyridoxine can reverse the seizure activity of acute isoniazid toxicity, large doses of pyridoxine (B6) are needed to completely reverse the symptoms. A case report is presented demonstrating the need for large doses of pyridoxine to reverse the symptoms of isoniazid intoxication and the literature of isoniazid toxicity in the pediatric age group is reviewed.