Pharmacology ch. 51

Hormones secreted from the adenohypophysis

1) Growth hormone (GH) stimulates growth in tissues and bone. Deficit-dwarfism; Excess-Giantism/ acromegaly 2) Thyroid-stimulating hormone (TSH) which acts on the thyroid gland 3) Adrenocorticotropic hormone (ACTH) stimulates the adrenal gland 4)Gonadotropins (follicle-stimulating hormone (FSH) and luteinizing hormone (LH)) which affect ovaries. *Regulated by negative feedback system

antidiuretic hormone (ADH)

ADH promotes water reabsorption form the rental tubules to maintain water balance in the body fluids. Where there is a deficiency of ADH, large amount of water are excreted by the kidneys. Interventions: monitor vitals (increased heart rate and decreased systolic pressure can indicate fluid volume loss resulting form decreased ADH production. With less ADH secretion, more water is secreted, decreasing vascular fluid), record urinary output (increased output can indicate fluid loss caused by decreased ADH)

Mineralocorticoid Drugs

Fludrocortisone (adrenocortical insufficiency, addison's disease). Can cause negative nitrogen balance; high protein diet is usually indicated. Serum potassium level should be monitored.

Anterior Lobe Hormone drugs

GH-somatropin (GH deficiency) GH suppressant-bromocriptine mesylate (for acromegaly), octreotide acetate (for acromegaly), Ianreotide acetate (suppress GH) TSH-thyrotropin (thyroid cancer) ACTH-corticotropin (to diagnose adrenocortical disorders, treat acute MS), cosyntropin (for diagnostic testing to differentiate between pituitary and adrenal cause of adrenal insufficiency)

Hypoparathyroidism

Hypocalcemia can be caused by PTH deficiency, vitamin D deficiency, renal impairment, or diuretic therapy, and PTH replacement helps correct the calcium deficit. Action of PTH is to promote reabsorption from the GI tract and renal tubules, and to activate vitamin D. Drug Therapies: calcitriol, ergocalciferol (hypoparathyroidism and rickets. enhances calcium and phosphorus absorption)

Hypothyroidism Drug Therapy

Levothyroxine sodium- increases levels of T3 and T4, also used to treat goiter and lymphocytic thyroiditis Liothyronine-a synthetic T3 that has a short half life and duration of action (not for maintenance therapy). initial therapy for myxedema. Liotrix- mixture of levothyroxine sodium and liothyronine sodium (4:1). Thyroid-natural form from animals Interactions: Increase the effect of oral anticoagulants because of drug displacement from the protein binding sites. Taken with adrenergic agent (decongestant or vasopressor) cardiac and CNS actions are increased. Insulin and oral antidiabetic drug dosages may need to be increased.

Drug Therapy Hyperthyroidism

Purpose is to reduce the excessive T3 and T4 by inhibiting thyroid secretion. The use of surgery and radioiodine therapy frequently leads to hypothyroidism. This drug group interferes with synthesis of thyroid hormone. Thioamides: Propylthiouracil (PTU)-inhibits conversion of T3 and T4. (may cause severe liver damage, liver failure, and death) Methimazole-inhibits thyroid hormone synthesis (rash, urticaria, headache, and GI upset may occur). Idoine: Potassium iodine-hyperthyroidism. To reduce size and vascularity of thyroid gland. Interactions: cause increase in the anticoagulation effect, decrease the effect of insulin, digoxin and lithium increase the action of thyroid drugs, phenytoin increases serum T3 levels.

Glucocorticoid Drugs

Short acting: Cortisone acetate (adrenocortical insufficiency, decreases inflammatory process); hydrocortisone ( adrenocortical insufficiency and inflammation) Intermediate: methylprednisolone (inflammatory conditions such as arthritis, bronchial asthma, allergic reactions, and cerebral edema); prednisolone (antiinflammatory or immunosuppressive effect); prednisone (decrease inflammatory occurrence, immunosuppressant, treat dermatologic disorders) Long acting: beclomethasone dipropionate (inhalation for bronchial asthma, bronchial inflammation, and seasonal rhinitis); betamethasone (potent antiinflammatory steriod drug), dexamethasone (Potent antiinflammatory durg, for acute allergic disorders, asthma attack, cereboral edema, and unresponsive shock) Interventions: vitals (increase BP and sodium and water retention); record weight (report weight gain of 5 lbs in several days); monitor lab values (electrolytes and BG), Watch for signs and symptoms of hypokalemia (nausea, vomiting, muscular weakness, abdominal distention, paralytic ileus, and irregular heart rate); assess for side effects from glucocorticoid drugs when therapy last more than 10 days, monitor older adults for signs and symptoms of increased osteoporosis (glucocorticoids promote calcium loss from bone), report changes in muscle strength (glucocorticoids promote loss of muscle tone), teach pt to avoid person with respiratory infections, drug suppress the immune system, report signs of overdose or cushing's syndrome: moon face, puffy eyelids, edema in feet, increased bruising, dizziness, bleeding, and menstrual irregularity, take at meal time or with food, eat foods rich in potassium.

adrenocorticotropic hormone (ACTH)

The hypothalamus releases corticotropin-releasing factor (CRF), which stimulates the pituitary corticotrophs to secrete ACTH. ACTH secretion stimulates the release of glucocorticoids (cortisol), mineralocorticoids (aldosterone), and androgen from the adrenal cortex. Interventions for replacement therapy: Repository Corticotropin: avoid administering corticotropin to pt with adrenocortical hyperfunction, monitor the growth and development of children, observe pt's weight. check for edema if weight gain occurs. side effect is sodium and water retention, dose should be tapered and not stopped abruptly because adrenal hypofunction may result, check lab findings (electrolyte levels), direct pt to decrease salt intake to decrease/avoid edema. potassium supplement may be needed, teach pt to report side effects (muscle weakness, edema, petechiae, ecchymosis, decrease in growth, decreased wound healing, and menstrual irregularities.

Growth hormone (GH)

Two hypothalamic hormones regulate GH: growth hormone releasing hormone (GH-RH) and growth hormone inhibiting hormone (GH-IH; somatostatin). Does not have a specific target gland; affects body tissues and bone. Interventions: monitor blood sugar and electrolyte levels in patients receiving GH. Hyperglycemia can occur with high doses,

Addison's disease

a decrease in corticosteroid secreation. adrenal hyposecretion (adrenal insufficiency)

Calcitriol

a vitamin D analogue that promotes calcium absorption form the GI tract and secretion of calcium from the bone to the bloodstream. to treat hypoparathyroidism and manage hypocalcemia in chronic liver failure.

adenohypophysis

anterior pituitary gland. "master gland" controlled by hypothalamus.

diabetes insipidus (DH)

can lead to severe fluid deficit and electrolyte imbalances

Hyperparathyroidism

caused by malignancies of the parathyroid glands or ectopic PTH hormone secretion from lung cancer, hyperthyroidism, or prolonged mobility, during which calcium is lost from bone. Drug therapies: Calcitonin-salmon- decreases serum calcium by binding at receptor sites; etidronate- hypercalcemia caused by antineoplastic therapy; cinacalcet-hyperparathyroidism and hypercalcemia.

cretinism

congenital hypothyroidism.

Adrenal glands

consist of the adrenal medulla and adrenal cortex. Adrenal cortex produces two types of hormones, or corticosteriods: glucorticoids (cortisol) and mineralocorticoids (aldosterone).

hypothyroidism

decrease in thyroid hormone secretion. Has a primary cause (thyroid gland disorder) or a secondary cause (lack of TSH secretion). Decreased T4 and elevated TSH levels indicate a primary hypothyroidism.

corticotropin drug interactions

diuretics and anti-psudomonas penicillins such as piperacillin can decrease the serum potassium level (hypokalemia). ACTH stimulates cortisol secretions which increases blood sugar level (may need to increase insulin). Phenytoin, rifampin, and barbiturates increase metabolic rate , which can decrease the effect of the ACTH drug.

endocrine

ductless glands that produce internal secretions that flow to all parts of the body

acromegaly

excessive growth after puberty

gigantism

excessive growth during childhood

Hyperthyroidism

increase in circulating T3 and T4 levels, which usually results from an overactive thyroid gland or excessive output of thyroid hormones from one or more thyroid nodules.

Cushing's syndrome

increase in corticosteroid secretion. adrenal hypersecretion

Glucocorticoids

influenced by ACTH, which is released from the anterior pituitary gland. they affect carbohydrate, protein, and fat metabolism and muscle and blood cell activity. Can cause sodium absorption from the kidney, resulting in water retention, potassium loss, and increased blood pressure. Cortisol has antiinflammatory, antiallergic, and antistress effects. Side effects: result from high doses or prolonged use include increased blood sugar, abnormal fat deposits in face and trunk, decreased extremity size, muscle wasting, edema, sodium and water retention, hypertension, euphoria or psychosis, thinned skin with purpura, increased intraocular pressure (glaucoma), peptic ulcers, and growth retardation. long term use can cause adrenal atrophy. the dose should be tapered to allow the adrenal cortex to produce cortisol and other corticosteroids. Abrupt withdrawal can result in severe adrenocortical insufficiency. Interactions: increase potency of drugs taken concurrently, aspirin and NSAIDs, thus increasing the risk for GI bleeding and ulceration. Use of lasix increases potassium loss, resulting in hypokalemia.

Graves' disease or thyrotoxicosis

most common type of hyperthyroidism caused by hyperfunction of the thyroid gland. Characterized by a rapid pulse, palpitations, excessive perspiration, heat intolerance, nervousness, irritability, exophthalmos (bulging eyes), and weight loss.

neurohypophysis

posterior pituitary gland secretes antidiuretic hormone (ADH) and oxytocin

Corticosteroids

promote sodium retention and postassium secretion.

Mineralocorticoids

second type of corticosteriod, secrete aldosterone. Aldosterone is controlled by the reninangiotensin system not ACTH. These hormones maintain fluid balance by promoting the reabsorption of sodium from the renal tubules. Sodium attracts water, resulting in water retention. When hypovolemia (decrease in circulating fluid) occurs, more aldosterone is secreted to increase sodium and water retention and restore fluid balance. with sodium reabsorption, postassium is lost and hypokalemia can occur.

thyroid stimulating hormone (TSH).

secreted by the anterior pituitary gland in response to thyroid releasing hormone (TRH) from the hypothalamus, and TSH stimulates the thyroid gland to release thyroxine (T4) and triiodothyronine (T3, or liothyronine). Excess TSH cause hyperthyroidism

Parathyroid hormone (PTH)

secreted by the parathyroid glands. Regulates calcium levels in the blood. A decrease in serum calcium stimulates the release of PTH. Calcitonin decreases serum calcium levels by promoting renal excretion of calcium.

thyroxine (t4) and triiodothyronine (T3)

secreted by the thyroid gland. The functions are to regulate protein synthesis and enzyme activity and to stimulate mitochondrial oxidation. The hypothalamus releases thyrotropin-releasing hormone (TRH), which stimulates the release of TSH from he pituitary gland. TSH stimulates the synthesis and release of T4 and T3 form the thyroid gland.

Myxedema

severe hypothyroidism in the adult; symptoms include lethargy, apathy, memory impairment, emotional changes, slow speech, deep coarse voice, edema of the eyelids and face, dry skin, cold intolerance, slow pulse, constipation, weight gain, and abnormal menses.

hypophysis

the pituitary gland. Has anterior and posterior lobe