Pyridoxine and the Isoniazid-Induced Neuropathy

¹ The Department of Medicine, University of California, School of Medicine and University of California Tuberculosis Service, San Francisco Hospital.

The isoniazid-induced peripheral neuropathy occurring in adult tuberculous patients results from a deficiency of biologically active pyridoxine. The deficiency is caused by the combination of isoniazid and pyridoxine to form a hydrazone which is excreted in the urine. It can be prevented by administration of pyridoxine whenever isoniazid is given. A 10 mg. dose of pyridoxine for each 100 mg. of isoniazid appears adequate to prevent both clinical and potential subclinical manifestations of pyridoxine deficiency. The administration of pyridoxine does not interfere with the antituberculous action of isoniazid.