To : Jeanne Fisher Re : Isovue(iopamidol) Iopamidol is a nonionic radiocontrast agent that is distributed between the circulating plasma and extracellular fluid with no deposition in tissues. Hence it is very unlikely to enter milk (but we have no data on this). The volume of distribution is 0.35 L/kg (exceedingly low which means its does not transfer into tissues very well). Iopamidol is excreted primarily unmetabolized through the kidneys which means the parent molecule does not release any free iodine. Iopamidol serum concentrations drop to 2-3 mg/100 cc of plasma at 12 hours. The apparent half-life is only 2 hours(which means 98% would be gone in 10 hrs). Further this product is routinely used in infants. As for breastfeeding, it is apparent that most is gone from the mom's plasma in about 10-12 hours. I believe it is very unlikely any would pass into milk. Further most in this family have no oral bioavailability. Regards Tom Hale, Ph.D.