Allergy Net Levothyroxine-induced hyperthyroidism.

The occurrence of levothyroxine-induced hyperthyroidism is rare but possible. Levothyroxine (LT) has been used for the treatment of hypothyroidism and for the suppression of thyroid-stimulating hormone levels in patients with thyroid nodules or thyroid gland enlargement. Allergic or idisyncratic reactions are extremely rare with the synthetic LT. There was a report of hypersensitivity caused by synthetic thyroid hormone in a hypothyroid patient with autoimmune Hashimoto's thyroiditis. Therefore, these adverse effects of the drug are of critical importance in the clinical management of patients.