To Janet Goodrich Re Herplex(idoxuridine) and Herpes keratoconjunctivitis First, Herpes keratoconjunctivitis is very dangerous and you need to tell that client to get started on this drug immediately, don't wait a minute or the risk of vision loss is high. Secondly, although there are numerous systemic side effects from IV idoxuridine, none of these problems seem to occur following ophthlamic use. This would suggest that the systemic absorption via eye drops is quite minimal. Some data may be available somewhere, but I cannot find it quickly. I cannot find anything on the oral bioavailability in a child. I doubt this product would be extremely hazardous to a breastfeeding infant simply because the maternal plasma levels would be minimal. Suggest mom breastfeed and then use the medication if she chooses to continue to breastfeed. Regards Tom Hale