The use of the iso-nicotinic acid hydrazides in the treatment of tuberculosis.

The iso-nicotinic acid hydrazides are valuable agents against tuberculosis exerting a powerful bacteriostatic action on the tubercle bacillus,’ diffusing readily into the cerebro spinal fluid,2 concentrating (as demonstrated by tissue cultures) effectively within macrophages3 and absorbed after oral administration without gastro-intestinal irritation. Such a combination of desirable attributes has not been exhibited by any other drug used in the treatment of tuberculosis. However, evidence has been presented that tubercle bacilli may become resistant4 to iso-nicotinic acid hydrazides after a therapeutic period of two months or less, especially in cases of chronic cavitary pulmonary tuberculosis; such bacterial resistance has usually been associated with clinical relapse. To prolong the beneficial action of the hydrazides, combined therapy with streptomycin and/or paraaminosalicylic acid has been suggested.