Ans. is 'd' i.e., Propylthiouracil oral o Graves' disease. an autoimmune disease characterized by antibodies against the thyrotropin (TSH) receptor (also called thyroid-stimulating immunoglobulins), is the most common cause of hyperthyroidism. Treatment of Graves disease o The therapeutic approach to Graves' hyperthyroidism consists of both # Rapid amelioration of symptoms with a beta-blocker # Measures aimed at decreasing thyroid hormone synthesis: the administration of a thionamide, radioiodine ablation, or surgery. i) Amelioration of symptoms Beta-blockers o Beta-blockers ameliorate the symptoms of hyperthyroidism that are caused by increased beta-adrenergic tone. o These include palpitations, tachycardia, tremulousness, anxiety, and heat intolerance. o Thus, a beta-blocker should be started (assuming there are no contraindications to its use) in most patients as soon as the diagnosis of hyperthyroidism is made, even before obtaining a 24-hour radioiodine uptake. ii) Drugs and measures used to decrease thyroid hormone synthesis Thionamides o The thioamide methimazole and propylthiouracil (PTU) are the primary drugs used to treat Graves' hyperthyroidism. o Methimazole is preferred because of its longer duration of action, allowing for once-daily dosing, more rapid efficacy, and lower incidence of side effects. o PTU is preferred during the first trimester of pregnancy because of the potential teratogenic effects of methimazole. o The goal of thionamide therapy in Graves' hyperthyroidism is to attain a euthyroid state within three to eight weeks. o This can be followed by ablative therapy with radioiodine or surgery' or by continuation of the drug for a prolonged period (usually one to two years) with the hope of attaining a permanent remission. iodinated contrast agents and pine o Patients who have severe hyperthyroidism or are allergic to thionamides may benefit from alternative medical therapies. o The oral radiocontrast agent's sodium iodate and iopanoic acid are potent inhibitors of the peripheral conversion of T4 to T3. o They are not used as primary therapy because of possible induction of resistant hyperthyroidism, o However, when given in combination with methimazole (at doses of500 to 1000 mg/day), they can rapidly ameliorate severe hyperthyroidism and can also be used to prepare a hyperthyroid patient for early surgery. Other medications - o A number of other medications have been used in the management of hyperthyroidism, including the following: o Glucocorticoids Inhibit peripheral T4 to T3 conversion and, in patients with Graves' hyperthyroidism, reduce thyroid secretion. They have been used in patients with severe hyperthyroidism and thyroid storm, although their efficacy is not well demonstrated. o Lithium Blocks thyroid hormone release, but its use has been limited by its toxicity. o Cholestyramine Given in a dose of 4 g four times daily with methimazole, lowers serum T4 and T3 concentrations more rapidly than methimazole alone, and may be useful adjunctive therapy in selected patients who require rapid amelioration of hyperthyroid symptoms. o Carnitine # Is a naturally occurring peripheral antagonist of thyroid hormone action that has been shown to ameliorate hyperthyroid symptoms and may prove to be useful clinically. o Rituximab A monoclonal antibody that causes peripheral B cell depletion, may induce a sustained remission in patients with Graves' disease and low TRAb levels, but its cost and side effects limit its utility. Radioiodine ablation o Radioiodine is widely used for the treatment of Graves' hyperthyroidism. o It has been the therapy of choice. o Although a thionamide provides control of hyperthyroidism as long as the drug is taken, the persistent remission rate when the drug is discontinued one to two years later averages only about 30 percent. However, there are patients in whom it may be reasonable to delay radioiodine (or surgery). Included in this group are patients with mild hyperthyroidism and patients with small goiters or with goiters that shrink during thionamide therapy. o Radioiodine is administered as a capsule or, less commonly, an oral solution of sodium 1311, which is rapidly absorbed from the GI tract and concentrated in thyroid tissue. o It induces extensive tissue damage, resulting in ablation of the thyroid within 6 to 18 weeks. The goal of radioiodine therapy is the destruction of the gland, with the early development of hypothyroidism. This eliminates the risk of recurrent hyperthyroidism. Surgery o Surgery is an unpopular therapy for Graves' hyperthyroidism, being selected by only 1 percent of thyroid specialists. o It is primarily indicated in patients who have an obstructive goiter or a very large goiter, in patients with active ophthalmopathy who desire definitive therapy for their hyperthyroidism, in pregnant women who are allergic to antithyroid drugs, and in patients who have allergies or poor compliance on antithyroid drugs but refuse radioiodine. Surgery would also be indicated if there was a coexisting suspicious or malignant thyroid nodule or primary hyperparathyroidism.