Article	Exp Clin Endocrinol Diabetes 2006; 114: 222-226 DOI: 10.1055/s-2006-924238
J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York
Influence of Short-Term Interruption of Antithyroid Drugs on the Outcome of Radioiodine Therapy of Graves' Disease: Results of a Prospective Study
S. M. Eschmann1, M. H. Thelen1, H. Dittmann1, R. Bares1
1 University of Tuebingen, Department of Nuclear Medicine, Tuebingen, Germany

Abstract

Aim: The factors influencing success of treating Graves' disease with radioiodine (¹³¹I) are discussed controversially. This study analyses prospectively the influence of discontinuing antithyroid drugs (ATD) immediately prior to treatment with radioiodine on the therapeutic outcome. Methods: We studied 141 patients with Graves' disease. In 73 of them (group A) treatment was performed under medication with ATD, in 68 patients (group B) ATD were discontinued for 3 - 7 days starting at the time of therapy. We performed a statistical analysis of the influence of ATD and other factors potentially influencing treatment results. Results: In group A 49/73 patients were treated successfully (67 %) vs. 58/68 (85 %) in group B (p < 0.01). Characteristic changes in the kinetics of radioiodine were observed: after discontinuing ATD specific uptake was higher (2.0 %/ml in group A vs. 2.6 %/ml in group B, p = 0.004), and the effective half life was longer (5.1 ± 1.3 d in group A vs. 5.5 ± 1.1 d in group B, p = 0.076) resulting in a significantly higher radiation dose in group B (200 ± 61 Gy in group A vs. 236 ± 72 Gy in group B, p = 0.002). Conclusion: We conclude that short-term interruption of ATD improves the success rate of treating Graves' disease with radioiodine significantly.

Key words

Radioactive iodine (RAI) therapy - Graves' disease - antithyroid drugs - dosimetry