Benefit of short‐term iodide supplementation to antithyroid drug treatment of thyrotoxicosis due to Graves’ disease

Abstract

Combined treatment with MMI and KI improved the short-term control of Graves' hyperthyroidism and was not associated with worsening hyperthyroidism or induction of thionamide resistance.

An Analysis for Aggravation of Thyroid Function After Discontinuing Potassium Iodine in Graves’ Patients Treated With Methimazole and Potassium Iodine

“…In a previous study, the group treated with MMI and KI showed more significant improvement of thyroid function than the group with only MMI at 2 -4 weeks after the therapy. From 8 weeks downward, this significant improvement was not observed [10]. These results suggest that KI contributed to normalization of thyroid function at the early period of GD treatment.…”

“…In other words, a role of KI for FT4 normalization is limited and relatively short. So, collecting together our finding and the previous finding [10], the cessation of KI or tapering of There is a report that excess iodine increased thyroid volume of GD patient [23]. Iodine, also known as an immune stimulant, may precipitate the onset of autoimmune thyroid disease and may be also directly toxic to the thyroid epithelial cell [24].…”

“…Considering these backgrounds, in many countries, MMI combined with KI therapy is seldom selected as the first-line therapy in GD patients. However, in Japan that is one of countries with sufficient dietary iodine intake, Takata et al reported the efficacy of MMI combined with KI as for the initial therapy in GD patients as far as reduction of a side effect of ATDs and early hormonal normalization [10]. In addition, Kasai et al reported the efficacy of propylthiouracil combined with small dose of iodine in the early period of GD treatment in Japan [21], and Hiraiwa et al reported that restriction of dietary iodine dose not ameliorate the early effect of ATD for GD patients in Japan [22].…”

“…In their report, when free T4 (FT4) was corrected to the normal range, KI was discontinued. After cessation of KI, transient aggravation of thyroid function was observed in 8.1-9.4% of patients [10]. However, little is known about the factors associated with the aggravation after cessation of KI.…”

“…Under these backgrounds, Takata et al reported that initial therapy using MMI combined with KI is useful to correct thyroid function in GD patients in Japan [10]. In their report, when free T4 (FT4) was corrected to the normal range, KI was discontinued.…”