The relevance of drug-induced organ pigmentation in animals

Postmortem examination of animals from long-term safety evaluation studies often reveals pigment deposition in tissues. A review of several such observations is given and the possible chemical backgrounds of their origin are described, in an attempt to aid the determination of relevance in individual cases. It is suggested that one may be fairly broad-minded in the interpretation of the relevance of such pigments, especially if they are found only in one species, and have no influence on the function of the organs involved. A final answer comes only after administration of the particular drug to man, although he is normally dosed at all events one should not overvalue the relevance of pigmentation found in long-term animal studies.