Endocrine Drugs

Question 1

Describe the hypothalamic-pituitary-endocrine gland axis

Answer 1

Hypothalamus receives input from periphery & brain, signaling hormones to produce more hormones from target endocrine glands. A negative feedback loop circulates hormones back to hypothalamus & pituitary to inhibit secretion

Question 2

Describe the Hypothalamus-Pituitary-THYROID Axis

Answer 2

• Hypothalamus tells anterior 
pituitary gland to release thyroid 
stimulating hormone (TSH) 
• TSH stimulates thyroid gland to 
increase iodide uptake and make 
thyroid hormone (T3 and T4) 
• T 3 (triiodothyronine) is active form 
• T4 (thyroxine) inactive but converted 
to T 3 in body 
• T3/T4 give negative feedback to 
hypothalamus/pituitary to reduce 
TSH release

Question 3

What is the MOA of levothyroxine?

Answer 3

Synthetic T4, replaces low levels of thyroid hormone

Question 4

Adverse effects of levothyroxine

Answer 4

insomnia, anxiety, sweating (hyperthyroid), and papilledema from idiopathic intracranial HTN (in children)

Question 5

Describe thyroid hormone synthesis

Answer 5

iodide in thyroid follicular cells + Thyroperoxidase + tyrosine residues of thyroglobulin=T3 and T4

Question 6

What is the MOA of methimazole for HYPERthyroid?

Answer 6

blocks thyroperoxidase enzyme, reducing T3/T4

Question 7

What are adverse effects of methimazole?

Answer 7

Lupus-like syndrome, alopecia, and myelosuppression (reduced blood cells)

Question 8

What is the MOA of radioactive iodine>

Answer 8

emits beta radiation, destroys thyroid cells, reducing T3/T4

Question 9

What drug(s) can lead to HYPOthyroid and fatigue?

Answer 9

radioactive iodine

Question 10

What drug treats thyroid eye disease?

Answer 10

teprotumumab

Question 11

What is the MOA of teprotumumab for TED?

Answer 11

inhibits IGF-1R, an autoantibody that increases orbital inflammation

Question 12

Side effects of teprotumumab for TED

Answer 12

hyperglycemia, alopecia, hearing impairment, muscle spasms

Question 13

What (2) hormones do estrogens & progestins inhibit?

Answer 13

hypothalamus release of FSH & LH

Question 14

What results from inhibiting FSH & LH?

Note that many drugs do this

Answer 14

No ovulation, endometrial lining thins/becomes inhospitable to eggs, cervical mucus thickens preventing sperm movement

Question 15

What is the major estrogen produced in the body

Answer 15

estradiol

Question 16

What are the 2 main combinations of estrogen-progestin contraceptives?

Answer 16

Norethindrone-ethinyl estradiol (ortho-novum) and norgestimate-ethinyl estradiol

Question 17

MOA of estrogen-progestin contraceptives

Answer 17

inhibit GnRH secretion from hypothalamus, decreasing FSH & LH

Question 18

Adverse effects of estrogen in contraceptives or menopause menopause

Answer 18

dry eye, papilledema, optic neuritis, risk of thromboembolism, increased coagulability of blood, pulmonary embolism, venous thrombosis, including vein occlusions in eyes

Question 19

Name the progestin only contraceptive

Answer 19

medroxyprogesterone (Depo-Provera; Provera)

Question 20

What is the MOA of medroxyprogesterone?

Answer 20

Progestin inhibits GnRH secretion from hypothalamus to reduce LH

Question 21

Adverse effects of progestin

Answer 21

Menstrual disturbances; must be taken perfectly & not as effective as combo contraceptives

Question 22

What is the MOA of estrogen (Premarin)?

Answer 22

Inhibits GnRH from hypothalamus, reducing FSH & LH surges that cause menopause symptoms

Question 23

Adverse effects of estrogen in menopause

Answer 23

Increased risk of stroke & venous thrombosis in women 50-79, risk of cardiovascular disorders, dementia, & endometrial cancer

Question 24

What is Danazol used for? (Danocrine)

Answer 24

endometriosis, was once used for macular edema

Question 25

What is the MOA of danazol in endometriosis? *

Answer 25

lowers estrogen production, inhibits hypothalamus, pituitary GnRH of FSH & LH; Causes atrophy of normal & ectopic endometrial tissue relieving symptoms

Question 26

What are the ocular side effects of Danazol?

Answer 26

Thromboembolism and papilledema (from idiopathic intracranial hypertension)

Question 27

What are the androgen and anti-estrogen side effects of danazol?

Answer 27

Male-like side effects: Hirsutism, weight gain, deep voice, & acne. Hot flashes, flushing, sweating; nausea, headaches & muscle cramps

Question 28

What are the 4 types of insulin?

Answer 28

1. Rapid acting, 2. Short acting (regular) 3. Long acting (NPH), and 4. Ultra long-acting

Question 29

What are the adverse effects of biguanide (metformin)?

Answer 29

nutritional optic atrophy/pallor, anemias; B12 deficiency, diarrhea, flatulence; risk for lactic acidosis in renal disease (decreases body pH, can be fatal)

Question 30

Why is metformin the 1st-line therapy for Type 2 DM?

Answer 30

it is the most effective, inexpensive, and does not cause hypoglycemia

Question 31

What are common side effects of SGL2 inhibitors (Canagliflozin & empagliflozin)?

Answer 31

dry eyes from dehydration, weight loss & reduced blood pressure, acute kidney injury, and genito-urinary fungal/yeast infections

Question 32

What is the MOA of SGLT2 inhibitors (canagliflozin and empagliflozin)?

Answer 32

Inhibit SGLT2 in proximal renal tubule to prevent glucose reabsorption & increase urinary glucose excretion

Question 33

Name (2) GLP-1 receptor agonists | Hint: suffix -tide; SC injections

Answer 33

dulaglutide (Trulicity) and exenatide (Byetta)

Question 34

What is the MOA of GLP-1 receptor agonists (dulaglutide & exenatide)?

Answer 34

stimulate glucose dependent insulin release from pancreas

Question 35

What is GLP-1?

Answer 35

A glucagon-like peptide; normally produced in gut that stimulates glucose release in pancreas

Question 36

What are side effects of GLP-1 agonists, (dulaglutide & exenatide)

Answer 36

Weight loss, pancreatitis, & risk of medullary thyroid cancer (in animals)

Question 37

What is the MOA of DPP4 inhibitors (sitagliptin & linagliptin)?

Answer 37

Inhibit DPP4 (dipeptidyl peptidase 4, which normally inactivates GLP-1) to stimulate glucose dependent insulin release from pancreas

Question 38

Side affects of DPP4 inhibitors (sitagliptin & linagliptin)?

Answer 38

pancreatitis & joint pain, myalgias