Carcinogenicity studies in rodents and ripazepam, a minor tranquilizing agent.

The carcinogenesis potential of ripazepam , a benzodiazepine derivative, was studied in mice and rats for 78 and 104 weeks, respectively. Groups of 50 male and 50 female CD1 mice and CD rats each were given doses of 15 and 150 mg/kg of ripazepam in the diet. Survival rates were adequate for statistical analysis. Significant suppression of body weight gains occurred in rats but not in mice given 150 mg/kg/day. The compound failed to increase tumor rates or alter the average latency of neoplasm in the rat, the number of male animals with tumors was increased at 150 mg/kg and this was related to a significant increase in the number of animals with hepatocellular tumors. Hepatocellular tumors were increased also in female mice but the increase was not statistically significant. All but one of these hepatic neoplasms were hepatocellular adenomas and the one carcinoma had not metastasized. Other tumor types were not increased.