Abstract
Objective: To highlight the possible complications of the treatment of hyperthyroidism with radioiodine 131. Bibliographic review: Hyperthyroidism is a clinical syndrome resulting from exposure of body tissues to high concentrations of thyroid hormones. The most common etiologies are Graves' disease, single hyperfunctioning adenomas, toxic multinodular goiter and Hashimoto's thyroiditis. In addition, it affects about 0.8% of the population in Europe and 1.3% in the USA, being more prevalent among females and white people. Radioiodo 131 is the first line of treatment for hyperthyroidism, being considered safe, easy to handle, low cost and efficient for the treatment of benign and malignant thyroid pathologies. Final considerations: Although this therapy has several benefits, some complications have been identified, such as the development of hypothyroidism, hematological and pulmonary changes, appearance of tumors, cardiomyopathies, damage to the thyroid of fetuses, and increased risk of exacerbation of ophthalmopathy. Thus, it is essential that the professional pay extra attention to patients with contraindications and assess the risk-benefit individually so that the ideal treatment is chosen.