[Demonstration of a correlation between the degree of pigmentation and the power of inactivation of isoniazid in man].

In a group of 153 white subjects treated for tubercle, individual determinations were made of: a) The power of inactivation of isoniazid. b) The degree of pigmentation (iris, skin, hair) assessed by a weighted pigmented index of the iris. A statistical study of the results shows the clear existence of a narrow positive correlation between these two characters, such that the more pigmented a subject is, the greater is the chance of rapid inactivation of isoniazid. An attempt at a biochemical explanation is proposed. The results in the world literature (Japanese, Swedish, American) are in keeping with these observations. Thus, weakly pigmented tuberculous patients are potentially a new group at risk from anti-TB drugs.