Thyroid and Antithyroid Drugs

Primary hypothyroidism myxocdeiiia) probably results in most cases from a ccll-niedialed immune response directed against the thyroid follicular cells. I evathyn xine is the drug of choice for replacement 

Thyrotroph in-re leasing hormone ( I KHt Ls a tripeptide synthesized in the hypothalamus and iran.sported in the capillaries of the pituitary portal venous system to the pituitary gland, where it. stimulates TSH synthesis and relea.se. 

Traditionally, young patient.s have been treated with antithyroid drugs and, if the condition relapses, subtotal thyroidectomy. Patients over about 40 years of age have been giv cn radioiodine therapy. Nowadays, young patients may be given 1 ami carbiniazolc may be given long-term. 

Carbimazak i.s rapidly converted to mcthimazole in vivo. The itim i.s to render the patient euthyroid tmd then to give a reduced dose for maitt-lenance. It is often possible to cease ireuimcm after 1 or 2 years. Side-effecl.s include rashes iincl, rarely, agranulocytosis (want patients to report a sore throat). 

Propylthiouracil is usually reserved for patients intolerant to car-biina/ole. It i.s associated with a higher incidence of agranulocytosis (0.4 Jf ) than carbimuzolc (0.1 %), In addition to inhibiting hormone synthesis. propylthiouracil also inhibits the peripheral dciodination of T4 and perhaps has an immunosuppres.sive action. 

Two diseases are related to the hormone-producing activity of the tiiyroid gland  

The symptoms of hypothyroidism and hyperthyroidism are given in Table 51-1. A severe form of hyperthyroidism, called thyrotoxicosis or tiiyroid storm, is characterized by high fever, extreme tachycardia, and altered mental status. Thyroid hormones are used to treat hypothyroidism and antithyroid 

Thyroid hormones used in medicine include both the natural and synthetic hormones. The synthetic hormones are generally preferred because they are more uniform in potency than are the natural hormones obtained from animals. Thyroid hormones are listed in the Summary Drug Table Thyroid and Antithyroid Dragp. 

The tiiyroid hormones influence every organ and tissue of tiie body. These hormones are principally concerned with increasing tiie metabolic rate of tissues, which results in increases in tiie heart and respiratory rate, body temperature, cardiac output, oxygen consumption, and the metabolism of fats, proteins, and carbohydrates. The exact mechanisms by which tiie tiiyroid hormones exert their influence 011 body organs and tissues are not well understood. 

Decreased with anorexia, intolerance to cold, low body temperature, weight gain despite anorexia 

Two diseases are related to tiie honnone-producing activity of tiie tiiyroid gland  

Thyroid honnones used in medicine include botii tiie natural and syntiietic honnones. The syntiietic hormones are generally preferred because tiiey are more mii-fonn in potency tiian are tiie natural honnones obtained from animals. Thyroid honnones are listed in tiie Suinmaiy Dmg Table Thyroid and Antitiiyroid Dm.  

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Discuss the uses, general drug actions, adverse reactions, contraindications, precautions, and interactions of thyroid and antithyroid drugs. 

Discuss important preadministration and ongoing assessment activities the nurse should perform on the patient taking thyroid and antithyroid drugs. 

Discuss ways to promote an optimal response to therapy, how to manage adverse reactions, and important points to keep in mind when educating patients about the use of thyroid and antithyroid drugs. 

SUMMARY DRUG TABLE THYROID AND ANTITHYROID DRUGS... 

Antithyroid dru inhibit the manufacture of thyroid hormones. They do not affect existing tiiyroid hormones tiiat are circulating in die blood or stored in die thyroid gland. For tiiis reason, therapeutic effects of the antithyroid drugs may not be observed for 3 to 4 weeks. Antithyroid drugs are listed in the Summary Drug Table Thyroid and Antithyroid Drugs. 

Farwell BP, Braverman LE. Thyroid and antithyroid drugs. In Brunton L, Lazo J, Parker K, eds. Goodman 8c Gilman s The Pharmacological Basis of Therapeutics. 11th ed. New York McGraw-Hill 2006 1511-1540. 

Christian, J.D., to Monsanto Chemical Company (1958), (1958) Imidazolidinethiones.US Patent 2,842,553 Chem. Abstr., 52, 20202c. Farwell, A.P. and Braverman, L.E. (2006) Thyroid and antithyroid drugs, in Goodman and Gilman s The Pharmacological Basis of Therapeutics, 11th edn (eds L.L., Brunton J.S., Lazo and K.L. Parker), McGraw-Hill, New York, pp. 1511-1540. 

J Crooks. Thyroid and antithyroid drugs. In L Meyler, A Herxheimer, eds. Side Effects of Drugs. Amsterdam Exerpta Medica, 1972. 

Farwell, A.P. and L.E. Braverman. Thyroid and antithyroid drugs. In Goodman and Gillman s the Pharmacological Basis of Medical Practice, 10th edition, edited by J.G. Hardman and L.E. Limbird, New York, McGraw-Hill, pp. 1563-1596, 2001. 

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