1. Drugs Used to Treat Thyroid Disease
Chapter 37
Drugs Used to Treat Thyroid Disease
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

2. Chapter 37
Lesson 37.1
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

3. Objectives Describe the function of the thyroid gland
Describe the signs, symptoms, treatment, and nursing interventions associated with hypothyroidism and hyperthyroidism
State the three types of treatment for hyperthyroidism
Identify the two classes of drugs used to treat thyroid disease
Explain the nutritional requirements and activity restrictions needed for an individual with hyperthyroidism
State the drug of choice for hypothyroidism
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

4. Objectives (cont’d)
Cite the actions of antithyroid medications on the formation and release of the hormones produced by the thyroid gland
Identify the types of conditions that respond favorably to the use of radioactive iodine-131
Cite the action of propylthiouracil on the synthesis of triiodothyronine and thyroxine
Explain the effects of hyperthyroidism on doses of warfarin and digoxin and on those taking oral hypoglycemic agents
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

5. Thyroid Functions
Hypothalamus secretes thyrotropin-releasing hormone (TRH)
Anterior pituitary secretes thyroid-stimulating hormone (TSH) in response to TRH
Thyroid gland secretes T3 and T4 in response to TSH
T3 and T4 regulate:
General body metabolism
Carbohydrate, protein, lipid metabolism
Thermal regulation
Cardiovascular function
Growth and maturation
Lactation and reproduction
Thyroid function is regulated by the hypothalamus and the anterior pituitary gland.
Synthesis of thyroid hormones depends on sufficient iodine intake through food and water.
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

6. Thyroid Disorders Hypothyroidism: inadequate thyroid hormones
Myxedema: occurs during adult life
Cretinism: born without a thyroid gland, or hypoactive one
Hyperthyroidism: excess production of thyroid hormones
Diseases causing overproduction: Graves’ disease, nodular goiter, thyroiditis, thyroid carcinoma, tumors of the pituitary gland
Overdose of thyroid hormones
Thyrotoxicosis: also known as hyperthyroidism
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

7. Treatment of Thyroid Disease
Goal of therapy
Return to a normal thyroid state
Two classes of drugs
Thyroid replacement hormones (hypothyroid)
Antithyroid agents (hyperthyroid)
Hyperthyroidism – three treatments used
Subtotal thyroidectomy
Radioactive iodine
Antithyroid medications
May be 1 to 3 weeks after drug initiation that the drug’s effects are noticed.
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

8. Nursing Interventions for Thyroid Disorders
Hypothyroidism
History of prior treatment for thyroid disorders, cardiac disease, or adrenal insufficiency
Request list of medications being taken
Perform focused assessment of body systems
Nutritional requirements (low-calorie diet)
Activity restrictions
Hyperthyroidism
Nutritional requirements (high-calorie diet)
Not all systems may be affected. Nursing care, diagnosis, and treatment focuses on affected systems.
Encourage moderate exercise as tolerated, focusing on safety during ambulation if muscle weakness, wasting, or discomfort is present.
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

9. Drug Class: Thyroid Replacement Hormones
Actions
Replace deficient T3 and T4 hormones
Uses
Return patient to normal thyroid state
Common and serious adverse effects
Signs of hyperthyroidism; hyperglycemia
Drug interactions
Warfarin, digoxin, estrogens, cholestyramine
For specific drugs, see Table 37-1.
Levothyroxine is the most commonly used medication.
Patients taking oral hypoglycemic agents or insulin may require adjustment.
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

10. Drug Class: Antithyroid Medicines
Drug: iodine-131 (131I)
Actions
Selectively destroy hyperactive thyroid tissue
Uses
Treat hyperthyroidism for select individuals
Common and serious adverse effects
Tenderness in the thyroid gland; hyperthyroidism; hypothyroidism
Drug interactions
Lithium carbonate
Used primarily for certain patients who may not be candidates for more aggressive treatment.
Iodine-131 is a radioactive isotope of iodine that is absorbed into the thyroid gland in high concentrations.
3 to 6 months for full benefit to be seen.
Extremely dangerous; wear latex gloves, watch for personnel who have allergies, follow hospital policy for spills.
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

11. Drug Class: Antithyroid Medicines (cont’d)
Drugs
Propylthiouracil (PTU, Propacil)
Methimazole (Tapazole)
Actions
Block synthesis of T3 and T4
Uses
Long-term treatment for hyperthyroidism
Presurgical treatment
Common and serious adverse effects
Purpuric, maculopapular rash; headache; nephrotoxicity; hepatotoxicity; bone marrow suppression, lymph node enlargement
Will not destroy T3 and T4 already produced; few days to 3 weeks before symptoms improve.
Drug interactions: warfarin dosage may have to be increased; digoxin dosage may have to be decreased.
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.