Two-day thionamide withdrawal prior to radioiodine uptake sufficiently increases uptake and does not exacerbate hyperthyroidism compared to 7-day withdrawal in Graves' disease.

Abstract

The appropriate period of antithyroid drug (ATD) discontinuation before radioiodine therapy is the most critical problem in Graves' disease patients under going treatment with ATD. To determine the optimal period that does not alter the outcome of radioiodine therapy or exacerbate hyperthyroidism, we compared serum FT4 levels at radioiodine uptake (RAIU) and therapy outcomes between a 2-day withdrawal group and 7-day withdrawal group. We prospectively recruited 43 patients for the 2-day withdrawal protocol and retrospectively reviewed 49 patients treated with radioiodine following the protocol of 7-day withdrawal. There was no significant difference in RAIU between the 2 groups. The mean serum FT4 level measured on the first day of 24-h RAIU of the 7-day group was significantly higher than that in the 2-day group. There were no significant differences in the outcomes at each point (6 months, 1 year, and 2 years after therapy) between the 2 groups. Our results indicated that withdrawal of ATD for 2 days is superior to 7 days in that 2 days discontinuation did not exacerbate hyperthyroidism. In order to prevent serum thyroid hormone increase after ATD withdrawal and radioiodine therapy, a 2-day ATD withdrawal period before radioiodine therapy may be useful for high-risk patients such as the elderly and patients with cardiac complications. We believe that the 2-day ATD withdrawal method may be useful for patients undergoing treatment with ATD who are to undergo radioiodine therapy.

• Authors: Sumihisa Kubota, Hidemi Ohye, Genichiro Yano, Eijun Nishihara, Takumi Kudo, Mitsuru Ito, Shuji Fukata, Nobuyuki Amino, Kanji Kuma, Akira Miyauchi
• Journal: Endocrine journal (Endocr J) Vol. 53 Issue 5 Pg. 603-7 (Oct 2006) ISSN: 0918-8959 [Print] Japan
• PMID: 16896267 (Publication Type: Comparative Study, Evaluation Study, Journal Article)

Chemical References

• Antithyroid Agents
• Iodine Isotopes
• Methimazole
• Propylthiouracil
• Thyroxine

Topics

• Adult
• Antithyroid Agents (administration & dosage, adverse effects)
• Drug Administration Schedule
• Female
• Graves Disease (drug therapy, radiotherapy)
• Humans
• Hyperthyroidism (drug therapy, radiotherapy)
• Iodine Isotopes (adverse effects, pharmacokinetics)
• Male
• Methimazole (administration & dosage, adverse effects)
• Middle Aged
• Propylthiouracil (administration & dosage, adverse effects)
• Retrospective Studies
• Thyroxine (blood)
• Treatment Outcome
• Withholding Treatment