Iopanoic acid and ipodate salts have been used for oral cholangiography to visualize the biliary ducts. Ipodate salts have been used for the long-term treatment of Graves' disease and in hyperthyroidism. Ipodate reduced levels of T3 and T4 in the patients. Ipodate also inhibits the conversion of T4 to T3. It is not considered a first-line approach. Ipodate sodium lacks FDA approval for these uses. During investigation of mechanism of action was discovered, that binding of sodium ipodate with nuclear T3 receptors was not a prominent mechanism via which the drug attenuates T3 effects in vivo. Sodium ipodate could enhance T3 effects at the cellular level and that enhancement could not be reflected by routinely monitored serum TSH.