DRUGS FOR PITUITARY, THYROID & ADRENAL DISORDERS

Question 1

What is the function of the hypothalamus and the pituitary gland?

Answer 1

Regulate the function of numerous endocrine glands
- hypothalamus secretes hormones that regulate function of the anterior pituitary
- hypothalamus controls the posterior pituitary through neuronal signaling

Question 2

What are pituitary endocrine disorders?

Answer 2

Occur as a result of tumor formation, congenital defect, surgery, radiation therapy, infection, hemorrhage or other injury
- many hormones are produced by pituitary, only a few are used clinically

Question 3

What is a growth hormone (somatroptin)?

Answer 3

Anterior pituitary hormone that stimulates growth and metabolism

Question 4

What is an anti diuretic hormone?

Answer 4

Stored and released by posterior pituitary in response to increased serum osmolality; ADH acts in the kidneys to increase water reabsorption

Question 5

What are the results from a growth hormone deficiency?

Answer 5

Short stature (children), decreased muscle mass, central adiposity, decreased bone density, dyslipidemia, increased cardiovascular mortality

Question 6

What does somatropin do?

Answer 6

Increases protein synthesis and lean muscle mass, bone density, lipid mobilization from fat stores improves lipid profile

Question 7

What are the results of pituitary disorders?

Answer 7

Excessive growth hormone production leading to:
- headache, bad vision
- enlarged heart, hands, feet, tongue, skull, nose, lips,
- deep voice
- sleep disorders

Question 8

What are the growth hormone antagonists?

Answer 8

• Octreotide
• Pegvisomamt

Question 9

What is Octreotide (growth hormone antagonist)?

Answer 9

Related to SOMATOSTATIN and inhibits the secretion of growth hormone and reduces tumour size

Question 10

What is Pegvisomant (growth hormone receptor antagonist)?

Answer 10

Blocks binding of somatotropin at growth hormone receptors in target tissues

Question 11

What is an antidiuretic hormone?

Answer 11

Causes the kidneys to release less water
- known as VASOPRESSIN (endogenous ligand/hormone)
- deficiency causes dilute urine and constant thirst

Question 12

What is desmopressin (agonist drug)?

Answer 12

• available as nasal spray, SC, IV and PO; prolonged duration of action
• does not exert same effects on BP as vasopressin (vasoconstrictor)

Question 13

How does the thyroid gland work?

Answer 13

• the hypothalamus produces thyrotropin-releasing hormone which stimulates the anterior pituitary to produce thyroid stimulating hormone (TSH)
• TSH induces the thyroid to produce and secrete triiodothyronine (T3- 10%) and thyroxine (T4- 90%)
  —T4 is converted to T3 in target tissues

These hormones regulate basal metabolic rate and impact the function of almost all major organ systems

Question 14

What is primary hypothyroidism?

Answer 14

Inactive thyroid gland commonly caused by an auto immune disease, women have a higher risk
- low serum T4, elevated TSH, increased anithyroid antibody

Question 15

What is secondary and tertiary hypothyroidism?

Answer 15

Low TSH from anterior pituitary gland or TRH from hypothalamus
- drug induced
- gestational hypothyroidism associated with low IQ in children, monitor TSH levels in 1st trimester of pregnancy

Question 16

What is Levothyroxine (Synthroid)?

Answer 16

• Reverses the effects of hypothyroidism by: increase metabolism, weight loss, increased activity an pulse rate
• regular monitoring of serum TSH levels required due to: increased cardiovascular demand
• effects: sweating, insomnia, rapid pulse, irritability etc

Question 17

What is Grave’s disease?

Answer 17

Autoimmune disorders, body develops antibodies that activate the TSH receptor, women at increased risk

Question 18

Function of Methimazole & Propylthiouracil (PTU)?

Answer 18

• thioamides that inhibit synthesis of thyroid hormone
• PTU disturbs conversion of T4 to T3 in target tissues, so faster inset
• therapeutic effect of metimazole can take 3-4 weeks

Question 19

What is radioactive iodine?

Answer 19

Single dose to permanently destroys follicular cells in overreactive thyroid gland; commonly used in cases of cancer

Question 20

What is the function of Glucocorticoids?

Answer 20

• increase blood glucose
• breakdowns of lipids an proteins
• suppress immune and inflammatory responses, stabilize mast cells
• increase vascular smooth muscle sensitivity to NE and angiotensin II
• affect mood
• decrease bone density
• bronchodilation

Question 21

What is the function of Mineralocorticoids?

Answer 21

Regulate plasma volume by conserving sodium and water and promoting potassium excretion by the kidney

Question 22

What is primary adrenal deficiency (Addison disease)?

Answer 22

Hypo-secretion of corticosteroids due to autoimmune destruction of both adrenal glands
- high ACTH, LOW CORTISOL, low aldosterone

Question 23

What is secondary adrenal insufficiency?

Answer 23

• inadequate secretion of ACTH from the anterior pituitary OR
• chronic long term corticosteroid therapy leading to adrenal atrophy

Question 24

What are non adrenal disorders?

Answer 24

Arthritis, allergies, asthma, lupus, Crohn’s disease, post transplant rejection, cancers, skin disorders

Question 25

What is the process of corticosteroid/glucocorticoid drugs?

Answer 25

• well absorbed an distributed, highly bound to plasma proteins
• metabolized by liver, excreted by kidneys
• crosses placenta, enters breast milk

Question 26

What is Cushing syndrome?

Answer 26

• metabolic disorder caused by excess secretion of corticosteroids due to excess amounts of ACTH…. OR
• prolonged high dose systemic glucocorticoid or corticosteroid drug therapy