The prevention and treatment of isoniazid toxicity in the therapy of pulmonary tuberculosis: 1. An assessment of two vitamin B preparations and glutamic acid.

This paper from the Tuberculosis Chemotherapy Centre, Madras, presents the results of a study designed primarily (a) to assess the efficacy of two preparations-Tab. Aneurin. Co. (a vitamin B compound not containing pyridoxine) and glutamic acid-in preventing the development of peripheral neuropathy during high-dosage (12.5-15.2 mg/kg) isoniazid therapy for pulmonary tuberculosis, and (b) to compare the therapeutic efficacy, once isoniazid neuropathy has developed, of Tab. Aneurin. Co., administered at twice the prophylactic dosage, and a vitamin-B-complex preparation containing a small amount of pyridoxine (amounting to 6 mg daily).Tab. Aneurin. Co. was found to be ineffective in preventing peripheral neuropathy, which occurred in five of the 18 patients receiving this preparation, as compared with six of the 18 who received a placebo, calcium gluconate. Glutamic acid appeared to have some prophylactic effect, since only two of the 19 patients receiving it developed the neuropathy, but the difference between the frequency in the glutamic series and that in the placebo series did not attain statistical significance.As to the therapeutic efficacy of the two vitamin B preparations, Tab. Aneurin. Co., at twice the prophylactic dosage, did not prevent the progression of the neuropathy in five out of seven patients, whereas improvement occurred in eight of the nine patients who received the vitamin-B-complex preparation containing the small amount of pyridoxine.This study has confirmed that the frequency of peripheral neuropathy is significantly higher among slow than among rapid inactivators of isoniazid and has indicated that the therapeutic response of the tuberculosis is not materially affected by increasing the dosage of isoniazid from 7.8-9.6 mg/kg (the dosage used in a previous study) to 12.5-15.2 mg/kg.