ntiate suspected mild hyperthyroidism or thyroid gland autonomy. liothyronine sodium tablets can be used in patients allergic to desiccated thyroid or thyroid extract derived from pork or beef.

r likelihood of occult cardiac disease. in these patients, liothyronine sodium therapy should be initiated with low doses, with due consideration for its relatively rapid onset of action. starting dosage of liothyronine sodium tablets is 5 mcg daily, and should be increased by no more than 5 mcg increments at 2-week intervals. when, in such patients, a euthyroid state can only be reached at the expense of an aggravation of the cardiovascular disease, thyroid hormone dosage should be reduced. morphologic hypogonadism and nephrosis should be ruled out before the drug is administered. if hypopituitarism is present, the adrenal deficiency must be corrected prior to starting the drug. myxedematous patients are very sensitive to thyroid; dosage should be started at a very low level and increased gradually. severe and prolonged hypothyroidism can lead to a decreased level of adrenocortical activity commensurate with the lowered metabolic state. when thyroid-replacement therapy is administered, the metabolism increases at a greater rate than adrenocortical activity. this can precipitate adrenocortical insufficiency. therefore, in severe and prolonged hypothyroidism, supplemental adrenocortical steroids may be necessary. in rare instances the administration of thyroid hormone may precipitate a hyperthyroid state or may aggravate existing hyperthyroidism.

nce the stated advantages. liothyronine sodium tablets may be used in preference to levothyroxine (t 4 ) during radioisotope scanning procedures, since induction of hypothyroidism in those cases is more abrupt and can be of shorter duration. it may also be preferred when impairment of peripheral conversion of t 4 to t 3 is suspected. myxedema: recommended starting dosage is 5 mcg daily. this may be increased by 5 to 10 mcg daily every 1 or 2 weeks. when 25 mcg daily is reached, dosage may be increased by 5 to 25 mcg every 1 or 2 weeks until a satisfactory therapeutic response is attained. usual maintenance dose is 50 to 100 mcg daily. myxedema coma: myxedema coma is usually precipitated in the hypothyroid patient of long standing by intercurrent illness or drugs such as sedatives and anesthetics and should be considered a medical emergency. an intravenous preparation of liothyronine sodium is marketed by jones pharma incorporated, under the trade name triostat® for use in myxedema coma/precoma. congenital hypothyroidism: recommended starting dosage is 5 mcg daily, with a 5 mcg increment every 3 to 4 days until the desired response is achieved. infants a few months old may require only 20 mcg daily for maintenance. at 1 year, 50 mcg daily may be required. above 3 years, full adult dosage may be necessary (see precautions, pediatric use ). simple (non-toxic) goiter: recommended starting dosage is 5 mcg daily. this dosage may be increased by 5 to 10 mcg daily every 1 or 2 weeks. when 25 mcg daily is reached, dosage may be increased every week or two by 12.5 or 25 mcg. usual maintenance dosage is 75 mcg daily. in the elderly or in pediatric patients, therapy should be started with 5 mcg daily and increased only by 5 mcg increments at the recommended intervals. when switching a patient to liothyronine sodium tablets from thyroid, l-thyroxine or thyroglobulin, discontinue the other medication, initiate liothyronine sodium at a low dosage, and increase gradually according to the patient's response. when selecting a starting dosage, bear in mind that this drug has a rapid onset of action, and that residual effects of the other thyroid preparation may persist for the first several weeks of therapy. thyroid suppression therapy: administration of thyroid hormone in doses higher than those produced physiologically by the gland results in suppression of the production of endogenous hormone. this is the basis for the thyroid suppression test and is used as an aid in the diagnosis of patients with signs of mild hyperthyroidism in whom baseline laboratory tests appear normal or to demonstrate thyroid gland autonomy in patients with graves’ ophthalmopathy. 131 i uptake is determined before and after the administration of the exogenous hormone. a 50% or greater suppression of uptake indicates a normal thyroid-pituitary axis and thus rules out thyroid gland autonomy. each 5 mcg tablet contains liothyronine sodium equivalent to 5 mcg of liothyronine. each 25 mcg tablet contains liothyronine sodium equivalent to 25 mcg of liothyronine. each 50 mcg tablet contains liothyronine sodium equivalent to 50 mcg of liothyronine. liothyronine sodium tablets are given in doses of 75 to 100 mcg/day for 7 days, and radioactive iodine uptake is determined before and after administration of the hormone. if thyroid function is under normal control, the radioiodine uptake will drop significantly after treatment. liothyronine sodium tablets should be administered cautiously to patients in whom there is a strong suspicion of thyroid gland autonomy, in view of the fact that the exogenous hormone effects will be additive to the endogenous source.

tivity which permits quick dosage adjustment and facilitates control of the effects of overdosage, should they occur. the higher affinity of levothyroxine (t 4 ) for both thyroid-binding globulin and thyroid-binding prealbumin as compared to triiodothyronine (t 3 ) partially explains the higher serum levels and longer half-life of the former hormone. both protein-bound hormones exist in reverse equilibrium with minute amounts of free hormone, the latter accounting for the metabolic activity.