Possible mutagenicity of the psychoactive phenothiazine derivative perazine in vivo and in vitro

Human lymphocyte cultures from 55 schizophrenic subjects and one manic-depressive subject being treated with the phenothiazine derivative perazine and with other drugs were analyzed with respect to chromosomal damage. The frequency of exchange-type aberrations in these subjects was more than double that in clinically normal control subjects. No correlation was detectable between the aberration frequency and sex, age, smoking and drinking habits, and treatment conditions. It is possible that the elevation of the chromosomal aberration frequency is due to perazine. In vitro studies with perazine and two main metabolites (desmethylperazine and perazine sulfoxide) with human lymphocytes and CHO cells with and without metabolic activation by liver microsomes gave negative results with respect to the induction of sister chromatid exchanges. Possible differences in the metabolism of perazine in vivo and in vitro are discussed.