[Demonstration of a correlation between the degree of pigmentation and the power of inactivation of isoniazid in man]. / Mise en évidence d'une corrélation entre le degré de pigmentation et la puissance d'inactivation de l'isoniazide chez l'homme.

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.

Power of isoniazid acetylation and pigmentation; first experimental tests in the rabbit: comparison with clinical data.

A positive correlation has been observed clinically at the Centre Edouard Rist, Paris, between the degree of pigmentation and the power of isoniazid acetylation in so-called "caucasians". The investigation was based on a relatively small sample of 153 observations, but sufficient to allow a significant statistical analysis. Comparing the results with data published in the literature, it may be assumed that this relationship between the power of acetylation and pigmentation would be applicable to all human beings. The rabbit, having as in man a bi-modal distribution of the power of acetylation, was used for further research of this correlation in that animal. The results of this research in rabbits may be compared with those in man, but further studies are required in view of the interest of this comparison and of the possible consequences of the relationship of pigmentation and the degree of acetylation of isoniazid in human therapeutics.