Nonradioactiveidoxuridine(IDU,5-iodo-2′-deoxyuridine), while not teratogenic to rats, does produce fetal malformations in rabbits when administered topically to the eye in doses similar to those used clinically, 0.1% four times a day for 12 days. These malformations include exophthalmos and clubbing of the forelegs. By contrast, trifluorothymidine (F3 TdR), another highly effective antiherpetic agent currently under investigation but not avail able for general use, was found not to be teratogenic to rabbits, even when given in concentrations tenfold greater than the doses used to produce idoxuridine teratogenicity.
Itoi M, Gefter JW, Kaneko N, Ishii Y, Ramer RM, Gasset AR. Teratogenicities of Ophthalmic DrugsI. Antiviral Ophthalmic Drugs. Arch Ophthalmol. 1975;93(1):46-51. doi:10.1001/archopht.1975.01010020050009