Physiology and pharmacology of iodized oil in goiter prophylaxis.

Thyroid complications resulting from excess iodide such as thyrotoxicosis, thyroiditis, sialadenitis, or hypothyroidism are much rarer after iodine supplementation with Lipiodol than with KI. They do not militate against its widespread use in endemic goiter populations, especially in pregnant women. However, patients with multinodular goiter should not be treated or should be treated only under careful observation. When Lipiodol-induced thyrotoxicosis occurs it tends to be mild or even subclinical and self-limited. If treatment is required, potassium perchlorate with or without thionamides is recommended. Iodide goiter has not been seen after Lipiodol supplementation, nor has thyroiditis. Sialadenitis occurs rarely. Iodide derived from Lipiodol readily enters the fetus, possibly by active transport, and theoretically endangers the fetus because autoregulation of the fetal thyroid occurs late during gestation. Despite the difficulty in distinguishing iodide goiter from iodide deficiency goiter of the newborn, no cases of neonatal iodide goiter have been reported. Possible mechanisms of thyroid inhibition by excess iodide are briefly discussed. The use of locally produced iodized plant oils is recommended for financial reasons as well as for the benefits derived from local participation.