Neonatal pyridoxine responsive convulsions due to isoniazid therapy.

A 17-day-old infant on isoniazid therapy 13 mg/kg daily from birth because of maternal tuberculosis was admitted after 4 days of clonic fits. No underlying infective or biochemical cause could be found. The fits ceased within 4 hours of administering intramuscular pyridoxine, suggesting an aetiology of pyridoxine deficiency secondary to isoniazid medication.