Comparative effects of sodium ipodate and iodide on serum thyroid hormone concentrations in patients with Graves' disease

E. Roti, G. Robuschi, A. Manfredi, L. D'Amato, E. Gardini, M. Salvi, M. Montermini, A. L. Barlli, A. Gnudi, L. E. Braverman

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Abstract

Patients with thyrotoxic Graves' disease were treated daily for 10 d with 1 g sodium ipodate, an iodine rich X-ray contrast agent which impairs outer ring (5'-) deiodination of T4 to T3, or with 12 drops of a saturated solution of potassium iodide (SSKI). T4, T3 and reverse T3 (rT3) concentrations were measured before, during, and 5 and 10 d after the administration of each drug. SSKI therapy induced a decrease in the serum T4 concentration from 14.7 ± 1.3 μg/dl (mean ± SE) to a nadir of 7.9 ± 0.9 on days 9 and 10 of therapy, all values reaching the normal range by day 9; a decrease in the serum T3 concentration from 402 ± 43 ng/dl to a nadir of 143 ± 20 on day 10, remaining elevated in all patients until day 5 and decreasing into the normal range in all except one patient on days 9 and 10; and no change in the serum rT3 concentration. Serum T4 and T3 concentrations returned to baseline values 10 d after withdrawal of SSKI. In contrast sodium ipodate therapy induced only a modest decrease in the serum T4 concentration from 15.1 ± 0.7 μg/dl to a nadir on day 9 of 11.3 ± 1.0 and serum T4 remained above the normal range in most patients until day 8; a striking and rapid decrease (within 12 h) in the serum T3 concentration from 340 ± 36 ng/dl to mean values ranging from 79 to 85 during the last 5 d of therapy, with most values below the normal range during the last 3 d; and a marked increase in the serum rT3 concentration from 111 ± 15 ng/dl to a peak value of 376 ± 59 on day 5. A significant rebound increase in serum T4 (18.7 ± 1.7 μg/dl; P <0.01) and serum T3 (512 ± 72; P <0.01) concentrations as compared to pretreatment values occurred 10 days after sodium ipodate was discontinued. We conclude that although treatment of hyperthyroidism with sodium ipodate induced a more rapid and more profound decrease in the serum T3 concentration than did SSKI, a marked rebound increase in serum T4 and T3 concentrations occurred after withdrawal of sodium ipodate but not after SSKI was discontinued.

Original languageEnglish
Pages (from-to)489-496
Number of pages8
JournalClinical Endocrinology
Volume22
Issue number4
Publication statusPublished - 1985

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ASJC Scopus subject areas

  • Endocrinology

Cite this

Roti, E., Robuschi, G., Manfredi, A., D'Amato, L., Gardini, E., Salvi, M., Montermini, M., Barlli, A. L., Gnudi, A., & Braverman, L. E. (1985). Comparative effects of sodium ipodate and iodide on serum thyroid hormone concentrations in patients with Graves' disease. Clinical Endocrinology, 22(4), 489-496.