The effect of iodine in patients using povidone-iodine mouth wash on thyroid function

Abstract

Background: Thyroid gland is a key part of endocrine system and it performs its functions via two most important thyroid hormones thyroxine (T4) and triiodothyronine (T3). Thyroid gland is mainly regulated by thyroid-stimulating hormone (TSH). Povidone-iodine (polyvinylpyrrolidone-iodine, PVP-I) mouthwash is commonly used to treat infections of the oral cavity and oropharynx and iodine released from PVP-I can interfere with thyroid function. In this study the effect of brief treatment with povidone-iodine mouth wash on thyroid function was assessed. The aim of the present study was to assess whether iodine is absorbed through oral transmucosal route and interfere with TSH in serum. Methods: Fifty one patients with acute and chronic pharyngitis and tonsillitis were recruited and out of which forty-seven patients were treated with 20 ml of PVP-I mouthwash twice daily for 3 weeks and blood was collected from the respective patients before and after treatment with PVP-I. Serum thyroid stimulating hormone concentration was measured from the collected blood samples of the patients. Results: In the present study there was a small increase in serum TSH concentration during the therapy with PVP-I but the concentration determined was within the normal range. Conclusions: Based on the results of this study we conclude that the use of PVP-I for a brief period transiently increase TSH value and prolonged use should be avoided in people with an increased risk of thyroid dysfunction and other autoimmune disorders.