[The conversion of hypothyroidism into hyperthyroidism during leflunomide with povidone iodine treatment of rheumatoid arthritis].

Till now there has not been reported data related to the influence of leflunomide on the thyroid gland function of the treated person. The authors described the case of woman with rheumathoid arthritis and hypothyroidism who revealed hyperthyroidism in 7 months after starting leflunomide tablets treatment containing povidone iodine as well. Also both autonomical tissue area in thyroid right lobe and hight TSHRAb level were found. Leflunomid tablets containing povidone iodine in its structure can cause hyperthyroidism in the person with previous hypothyroidism and nodular goiter, probably as a result of immunological reconversion and tissue nodular functional autonomisation. In persons with nodular goitre one should prefer free of povidone iodine leflunomide treatment and also monitor serum thyroid hormone contents and thyroid antibodies as well.