The use of oral radiographic contrast agents in the management of hyperthyroidism

Oral iodinated radiographic contrast agents such as ipodate and iopanoic ac id form an important part of the armamentarium used to treat hyperthyroidis m. They rapidly and dramatically reduce serum triiodothyronine (T-3) levels by inhibiting conversion of thyroxine (T-4) to T-3 in the periphery and by blocking secretion from the thyroid. Potential risks from the large iodine load resulting from their use limit their widespread applicability. In add ition, they are ineffective when used alone on a long-term basis. However, these agents may be especially useful in treating thyrotoxic patients preop eratively, in neonatal Craves' disease, in massive levothyroxine ingestion, and when other conventional antithyroid drugs are unsuccessful or contrain dicated.