PERIPHERAL NEURITIS FOLLOWING ISONIAZID THERAPY

Abstract

Several articles have appeared describing the neurotoxic effects of isoniazid (isonicotinic acid hydrazide). The disorder is primarily peripheral in distribution, with the stocking-and-glove type of sensory changes. If administration of isoniazid is continued, the symptoms increase in severity and extend to more proximal portions of the extremities. Motor symptoms tend to be mild. Reflex changes when present vary; hyperactivity to complete loss of the deep tendon reflexes have been described. If administration of the medicament is discontinued soon after the appearance of these symptoms, the symptoms have been found to disappear. In the more severe cases, the symptoms tend to persist. The B vitamins, excepting pyridoxine, have been used to counteract these reactions without notable effect. The studies of Biehl and Vilter demonstrated increased urinary excretion of pyridoxine in cases of neuritis caused by isoniazid. The excretion of pyridoxine increased proportionately with the dosage of isoniazid. With high doses of