Doxefazepam

Groups of 50 male and 50 female Sprague-Dawley rats are given food containing sufficient Doxefazepam, a benzodiazepine derivative, to ensure intakes of 0, 3, 10, or 30 mg/kg/day. Rats are treated for 104 weeks and then euthanized. An extensive autopsy is performed on those animals that died intercurrently and on euthanized animals. The chronic administration of Doxefazepam does not influence the survival of the rats. A significant linear trend in the incidence of hepatocellular neoplasms, primarily benign, is observed in the female treated groups. This higher incidence is not associated to a higher occurrence of focal hyperplasia or other preneoplastic lesions in treated rats. The brain, a target organ for the pharmacological activity of Doxefazepam, is carefully examined to search for microscopic foci of proliferative cells. A total of 12 and 6 malignant gliomas are observed in male and female rats, respectively; only two are noticed at autopsy. These tumors are mainly of the oligodendroglioma type commonly found in aged rats^[1]. Doxefazepam is investigated in a series of toxicological studies. Oral LD₅₀ values are greater than 2000 mg/kg in mice, rats and dogs, while endoperitoneal LD₅₀ values are 746 and 544 mg/kg in the mice and rats, respectively, and greater than 1000 mg/kg in the dogs^[2].