Effects of iodinated glycerol on thyroid function studies in elderly nursing home residents.

Iodinated glycerol is used as a mucolytic expectorant in the treatment of respiratory disorders. Iodine can inhibit the biosynthesis of thyroid hormone and induce hypothyroidism, particularly in patients with a history of thyroid disease. Such effects have not been reported in individuals without known thyroid disease who are being treated with organically bound iodine in the form of iodinated glycerol. In the course of a thyroid screening program for nursing home residents, eight subjects were identified who were being treated with iodinated glycerol. Five of these were found to have thyrotropin elevations; one showed a low serum thyroxine level and a decreased free thyroxine index. None of these residents had a history of thyroid disease. Abnormalities of thyroid function improved or resolved after discontinuation of therapy. Elderly nursing home residents without known thyroid disease are at risk of thyroid suppression when given iodinated glycerol.