Reproductive toxicity Lewisite

The Army s interim RfD of 1 x 10 " mg/kg per day for lewisite was based on two oral studies a two-generation reproductive study and a 90-day toxicity study in rats. In both studies, necrosis and hyperplasia of the forestomach were observed. After considering those studies and other potential studies, the subcommittee concludes that a 1987 teratogenicity study conducted in rabbits is more appropriate than the rat studies for deriving the RfD, because there is evidence that the rabbit might be more susceptible to lewisite than the rat. On the basis of the rabbit study, in which maternal mortality and gastric lesions were observed, the snbcommittee believes that the RfD for lewisite should be lowered from 1 x 10 mg/kg per day to 1 x 10 mg/kg per day. 

Multigeneration reproductive studies in rats (Sasser et al, 1989b) and teratology studies in rats and rabbits (Hackett et al, 1987) given lewisite by gastric intubation were negative or compromised by concurrent maternal toxicity. 

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