Case Report: Acute isoniazid intoxication after intentional ingestion

Abstract

Isoniazid is an anti-tuberculosis medication that is extensively used for treatment and prevention of tuberculosis. Acute isoniazid poisoning is characterized by a clinical triad of recurrent seizures, raised anion gap metabolic acidosis and coma. The seizures are unresponsive to standard anticonvulsant drugs, instead requiring pyridoxine administered in a dose equal to the amount of isoniazid consumed. Due to the high incidence of tuberculosis in low-income countries like Nepal, isoniazid intoxication should be considered in any patient who present with such unresponsive seizures and coma. We report a case of a 31 years old woman from Nepal, who intentionally ingested 12 grams of isoniazid and presented with generalized tonic-clonic seizures. She was successfully managed with 10 grams of pyridoxine along with other supportive management, including sodium bicarbonate for metabolic acidosis and mechanical ventilation. Doctors working in low-income countries, like Nepal, where tuberculosis is endemic, should be well acquainted with presentations and management of isoniazid intoxication.