This article is more than 5 years old. Information may no longer be current.
Efficacy of potassium iodide better in patients with less-severe hyperthyroidism in Graves’ disease
Click Here to Manage Email Alerts
Patients with Graves’ disease who were switched from treatment with thionamides to potassium iodide therapy had better outcomes when they had lower, compared with higher, levels of free triiodothyronine and free thyroxine on the day of the switch, according to researchers from Japan.
“Inorganic iodine has been used to treat patients with Graves’ disease for 100 years. ... After thionamides, such as thiamazole and propylthiouracil, became available, inorganic iodine became an alternative treatment, as a transient treatment option for Graves’ thyrotoxicosis planning for thyroid surgery or with thyroid crisis,” Toyoyoshi Uchida, MD, PhD, of the department of metabolism and endocrinology at Juntendo University Graduate School of Medicine, Tokyo, and colleagues wrote. “Thus, in the clinical setting, it has been difficult to elucidate the long-term therapeutic effects of inorganic iodine on Graves’ thyrotoxicosis in a prospective study.”
Uchida and colleagues performed a retrospective cohort study of 24 Japanese patients with Graves’ disease whose treatment was switched from thionamides to potassium iodide to alleviate adverse effects of thionamides. The researchers divided patients into two groups: those who did not maintain euthyroid function for 180 days (recurrence group, n = 13) and those who remained euthyroid for 180 days or more (non-recurrence group, n = 11).
On the day of treatment change, patients in the recurrence group had higher levels of free triiodothyronine (FT3) and free thyroxine (FT4) compared with those in the non-recurrence group (FT3, 9.3 pg/mL vs. 3.7 pg/mL; FT4, 3.6 ng/dL vs. 1.4 ng/dL; P = .02 for both). FT4 levels remained higher in the recurrence group even after the researchers adjusted for dosage of either thionamides or potassium iodide, Uchida and colleagues wrote. Duration of potassium iodide effect in the recurrence group was inversely correlated with FT3 and FT4 levels on the day of drug change.
“In our present study, the long-term efficacy is expected when the thyroid hormone levels are within normal range on the day of the drug change, but efficacy is inversely correlated with the severity of thyrotoxicosis,” Uchida and colleagues wrote. – by Andy Polhamus
Disclosures: The authors report no relevant financial disclosures.
Click Here to Manage Email Alerts