Acute isoniazid neurotoxicity during preventive therapy

Objective: To describe rare side effects of treatment with isoniazid. Design: Descriptive case report. Setting: Medical intensive care unit in a university medical center. Patient A 14-yr old previously healthy girl receiving preventive isoniazid therapy who suddenly developed generalized tonic-clonic seizures and coma, Interventions: Patient was sedated and mechanically ventilated. She also re ceived pyridoxine intravenously. Measurements and Main Results: An isoniazid overdose was not confirmed. Com puted tomography of the brain and electroencephalogram revealed nothing abn ormal. Seizures gradually disappeared within 2 hrs after sedation and treat ment with pyridoxine. The patient was discharged on day 14 without conseque nces and has been well for 10 mos, No seizures reappeared after isoniazid w as discontinued. Conclusions: We caution against possible isoniazid neurotoxicity in healthy individuals using recommended preventive doses.