• Clorazepate dipotassium (Tranxene), an anticonvulsant benzodiazepine, was tested for teratogenicity by injecting ten pregnant Long-Evans rats with 32 mg/kg of body weight intramuscularly on days 8.5, 9.5, and 10.5 of gestation. Ten control rats similarly received sterile water injections. Sixty fetuses recovered after killing five of the mothers on day 20.5 of gestation were sectioned to ascertain external and visceral malformations. Comparison with 55 control fetuses showed no statistically significant differences in external, visceral, or skeletal malformations, nor in fetal mortality, fetal and placental weight, and crown-rump length. Five clorazepate-treated rat mothers were allowed to deliver their 45 offspring for a companion study of possible behavioral effects. None of these additional 45 clorazepate-treated rats showed external malformations. Thus, clorazepate caused no gross malformations in the rat under the conditions of this study.
Corwin H, DeMyer W. Failure of Clorazepate to Cause Malformations or Fetal Wastage in the Rat. Arch Neurol. 1980;37(6):347–349. doi:10.1001/archneur.1980.00500550049004
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