Levothyroxine Sodium Tablet (Thydin) is used as a replacement therapy for hypothyroidism of any etiology or as an adjuvant with anti-thyroid preparations to prevent hypothyroidism. It is used to suppress Thyroid Stimulating Hormone (TSH) in simple non-toxic goiter, such as thyroid nodules and Hashimoto's thyroiditis, and post therapeutic treatment for radiological or surgical operation. Levothyroxine Sodium Tablet (Thydin) is concomitantly given to patients undergoing thyroid suppression test and to patients taking drugs with goitrogenic effects such as lithium.