A comparison of the teratogenic activity of thalidomide in rabbits and rats.

The teratogenic potency of thalidomide has been compared in rabbits and rats. After p.o. administration in daily doses ranging from 25 to 200 mg/kg, thalidomide was markedly teratogenic in rabbits but only slightly so in rats. After i.v. injection of the drug dissolved in dimethyl sulfoxide or propylene glycol, teratogenic effects were observed both in rabbits receiving daily doses as low as 2.5 to 10 mg/kg and in rats receiving doses of 10 mg/kg. Thus, after i.v. injection, thalidomide is only 2 to 4 times as potent in rabbits as in rats.