Fluoride Therapy and The Thyroid Gland

To the Editor:—  The usefulness of high-dose oral sodium fluoride therapy in the treatment of various demineralizing disorders has been reported by a number of authors.^1-4 Fluoride, however, is known to be an antithyroid agent and has been used to treat hyperthyroidism.⁵ Recently we have observed a patient with multiple myeloma whose clinical deterioration during fluoride administration may be attributed to the development of hypothyroidism. Thyroid replacement therapy has resulted in significant clinical improvement.

Report of a Case:—  A 59-year-old housewife was followed up in the clinics of the Bronx Municipal Hospital Center. The diagnosis of multiple myeloma had been made elsewhere five years ago (1961). Severe low back pain was noted initially in 1963, and was treated with radiotherapy and urethane. The patient was first seen here in 1964 when β-myeloma was confirmed and roentgenograms of the skull and spine revealed osteolytic lesions and collapse of several