Teratogenic evaluation of triclabendazole in rats.

Triclabendazole, a new benzimidazole anthelmintic, was administered by gavage to pregnant rats at 0 (control), 10, 25, 50, 100 or 200 mg/kg on days 8 through 15 of pregnancy. The dams were killed on day 21 of pregnancy, and the fetuses were examined by routine teratological methods. As the results, no increase in the incidence of resorptions was observed even at 200 mg/kg corresponding to 20 times the recommended therapeutic dose. There was a dose-related decrease in fetal body weights which was statistically significant at 100 mg/kg or more. Examinations of the fetuses revealed no significant increase in the incidences of gross, skeletal and internal malformations at any dose in comparison with the controls. Thus, no evidence of embryocidal and teratogenic effects was observed with this anthelmintic in rats.