1 Drugs for Thyroid Disorders Chapter 58

2 Stimulation of energy use Stimulation of the heart Promotion of growth & development Thyroid Hormone Actions

3 Thyroid

4 Figure 58-2 Steps in thyroid hormone synthesis.

5 Hypothalamus – Releasing Factors

6 Figure 58-3 Regulation of thyroid function.

7 Lab Tests Thyroid Stimulating Hormone is the best test of thyroid function Except in the case of…

8 Thyroid Problems Hypo Cold skin Dry skin & hair Low HR Lethargy Weight gain Cold intolerance Hyper Increased body temp Skin warm & moist Elevated HR Nervous, insomnia Weight loss Increased appetite

9 Hypothyroidism Severe deficiency of thyroid hormone –Myxedema (adults) –Cretinism (infancy) Top Causes –Autoimmune (Hashimoto’s thyroiditis) –Iodine deficiency

10 Hypothyroidism (cont’d) Therapeutic strategy –Levothyroxine (T 4 ) –Liothyronine (T 3 )

11 Thyroid Hormone Preparations Levothyroxine (T 4 ) [Synthroid] –Synthetic preparation of thyroxine (T 4 ) –Conversion to T 3 –Half-life is 7 days –Used for all forms of hypothyroidism –Adverse effects can you anticipate what these might be?

12 Hypothyroidism (cont’d) Therapeutic goal? When to dose? When to recheck TSH? What happens to dosing in pregnancy?

13 Hyperthyroidism Two major forms of hyperthyroidism –Graves’ disease (most common) –Toxic nodular goiter (Plummer’s disease)

14 Hyperthyroidism (cont’d) Cause of Grave’s disease –Thyroid-stimulating immunoglobulins (TSIs) Treatment –Suppression of thyroid hormone synthesis –Surgical removal of thyroid tissue –Destruction of thyroid tissue

15 Propylthiouracil (PTU) Inhibits thyroid hormone synthesis Short half-life (about 75 minutes) Therapeutic uses –Graves’ disease –Adjunct to radiation therapy –Preparation for thyroid gland surgery Adverse effects –Agranulocytosis –Hypothyroidism Caution in Pregnancy and lactation

16 Methimazole First line drug Inhibits thyroid hormone synthesis Is safer and more convenient than PTU Is contraindicated during pregnancy and breastfeeding

17 Radioactive Iodine-131 ( 131 I) Radioactive isotope of stable iodine Emits gamma and beta rays Half-life is 8 days Used in Graves’ disease Action –Produces clinical remission with destruction of thyroid gland

18 Exophthalmos & Goiter Which is hypothyroid and which is hyperthyroid?

19 Case A 25-year-old, previously healthy woman presents with 1 month of anxiety, palpitations, loose stools, fine tremors, and hair loss. 20-pound weight loss over past 4 months, increased appetite. HR 115 to 130 BPM, T 37.5C. Exam notable for mild bilateral proptosis, thin hair, and moist skin. Goiter visible with audible bruit. Hyperreflexia and fine tremors. EKG – normal sinus tachycardia.

20 Question When caring for a client in thyroid crisis (storm), the nurse would question an order for… IV Fluids Propranolol PTU Hyperthermia (warming) blanket

21 Question A client is prescribed Synthroid daily. The most important instruction to give her is… Taper dose & dc if mental and emotional statuses stabilize. Take it at bedtime to avoid side effects of nausea and flatus. Call the doctor immediately at the onset of palpitations or nervousness. Decrease intake of juices and fruits with high potassium and calcium contents.

22 Drugs for Disorders of the Adrenal Cortex Chapters 60 & 72

23 Physiology of the Adrenocortical Hormones Three classes of steroid hormones –Glucocorticoids- cortisol –Mineralocorticoids- aldosterone –Androgens- androstenedione

24 Glucocorticoids—Physiologic Effects Carbohydrate metabolism Protein metabolism Fat metabolism Cardiovascular system Skeletal muscle Central nervous system Stress Respiratory system in neonates

25 Figure 60-2 Negative feedback regulation of glucocorticoid synthesis and secretion.

26 Adrenocortical Hormones Mineralocorticoids –Circulatory balance –Retention of sodium (Na+) & water –Excretion of potassium (K+)

27 Physiology of the Adrenocortical Hormones Two most familiar forms of adrenocortical dysfunction –Adrenal hormone excess Cushing’s syndrome –Adrenal hormone deficiency Addison’s disease

28 Cushing’s syndrome

29 Adrenal Hormone Excess Cushing’s syndrome –Causes Hypersecretion of adrenocorticotropic hormone (ACTH) Hypersecretion of glucocorticoids Administering glucocorticoids in large doses

30 Adrenal Hormone Excess (cont’d) Cushing’s syndrome (cont’d) –Treatment Surgical removal of the adrenal gland Replacement therapy

31 Adrenal Hormone Insufficiency Addison’s disease Primary Adrenocortical Insufficiency –  Causes - most often caused by autoimmune disease Acute adrenal insufficiency (adrenal crisis) Causes –Adrenal failure –Pituitary failure –Inadequate doses of corticosteroids

32 Adrenal Hormone Insufficiency Addison’s disease Symptoms Hypoglycemia Malaise Loss of appetite Reduced capacity to respond to stress Treatment Rapid replacement of fluid, salt, and glucocorticoids Hydrocortisone is the drug of choice –Increase in time of physiologic stress – 3x3 rule

33 Hydrocortisone Synthetic steroid Therapeutic uses –Adrenal insufficiency –Allergic reactions to inflammation to cancer Adverse effects –Adrenal suppression –Cushing’s syndrome

34 Glucocorticoids DrugPhysiologic dose Non- endocrine dose Relative GC efficacy Relative MC efficacy Hydrocortisone20-25 mgUp to 240 mg (up to 800 mg in MS!) Prednisone5-10 mgUp to mg Dexamethosone mgUp to 9 mg See Table 7.2

35 Fludrocortisone [Florinef] Potent mineralocorticoid Therapeutic uses –Addison’s disease –Primary hypoaldosteronism –Congenital adrenal hyperplasia

36 Fludrocortisone [Florinef] Adverse effects –Hypertension –Edema –Cardiac enlargement –Hypokalemia

37 Glucocorticoids in Nonendocrine Diseases Glucocorticoid physiology –Metabolic effects –Cardiovascular effects –Effects during stress –Effects on water and electrolytes –Respiratory system in neonates Physiologic vs. Pharmacologic doses What is the difference?

38 Pharmacology of the Glucocorticoids Effects on metabolism and electrolytes Anti-inflammatory and immunosuppressant effects Therapeutic uses in nonendocrine disorders –Rheumatoid arthritis –Systemic lupus erythematosus –Inflammatory bowel disease –Miscellaneous inflammatory disorders

39 Pharmacology of the Glucocorticoids (cont’d) Therapeutic uses in nonendocrine disorders (cont’d) –Allergic conditions –Asthma –Dermatologic disorders –Neoplasms –Suppression of allograft rejection –Prevention of respiratory distress syndrome

40 Pharmacology of the Glucocorticoids (cont’d) Adverse effects –Adrenal insufficiency –Osteoporosis –Infection –Glucose intolerance –Myopathy –Fluid and electrolyte disturbance –Growth retardation –Psychologic disturbances

41 Pharmacology of the Glucocorticoids (cont’d) Adverse effects (cont’d) –Cataracts and glaucoma –Peptic ulcer disease –Iatrogenic Cushing’s syndrome

42 Pharmacology of the Glucocorticoids (cont’d) Development of adrenal suppression –Exogenous vs. endogenous Adrenal suppression and physiologic stress Glucocorticoid withdrawal –Taper the dosage over 7 days –Switch from multiple doses to single doses –Taper the dosage to 50% of physiologic values –Monitor for signs of insufficiency

43 Question A nurse knows the clinical manifestations of a client with Addison’s disease include… Weight gain Hypertension Melanosis Hypotension Hyponatremia

44 Question A nurse knows the clinical manifestations of a client with Addison’s disease include… Weight gain Hypertension Melanosis Hypotension Hyponatremia