Endocrine Drugs Flashcards
Describe the hypothalamic-pituitary-endocrine gland axis
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
Describe the Hypothalamus-Pituitary-THYROID Axis
• 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
What is the MOA of levothyroxine?
Synthetic T4, replaces low levels of thyroid hormone
Adverse effects of levothyroxine
insomnia, anxiety, sweating (hyperthyroid), and papilledema from idiopathic intracranial HTN (in children)
Describe thyroid hormone synthesis
iodide in thyroid follicular cells + Thyroperoxidase + tyrosine residues of thyroglobulin=T3 and T4
What is the MOA of methimazole for HYPERthyroid?
blocks thyroperoxidase enzyme, reducing T3/T4
What are adverse effects of methimazole?
Lupus-like syndrome, alopecia, and myelosuppression (reduced blood cells)
What is the MOA of radioactive iodine>
emits beta radiation, destroys thyroid cells, reducing T3/T4
What drug(s) can lead to HYPOthyroid and fatigue?
radioactive iodine
What drug treats thyroid eye disease?
teprotumumab
What is the MOA of teprotumumab for TED?
inhibits IGF-1R, an autoantibody that increases orbital inflammation
Side effects of teprotumumab for TED
hyperglycemia, alopecia, hearing impairment, muscle spasms
What (2) hormones do estrogens & progestins inhibit?
hypothalamus release of FSH & LH
What results from inhibiting FSH & LH?
Note that many drugs do this
No ovulation, endometrial lining thins/becomes inhospitable to eggs, cervical mucus thickens preventing sperm movement
What is the major estrogen produced in the body
estradiol
What are the 2 main combinations of estrogen-progestin contraceptives?
Norethindrone-ethinyl estradiol (ortho-novum) and norgestimate-ethinyl estradiol
MOA of estrogen-progestin contraceptives
inhibit GnRH secretion from hypothalamus, decreasing FSH & LH
Adverse effects of estrogen in contraceptives or menopause menopause
dry eye, papilledema, optic neuritis, risk of thromboembolism, increased coagulability of blood, pulmonary embolism, venous thrombosis, including vein occlusions in eyes
Name the progestin only contraceptive
medroxyprogesterone (Depo-Provera; Provera)
What is the MOA of medroxyprogesterone?
Progestin inhibits GnRH secretion from hypothalamus to reduce LH
Adverse effects of progestin
Menstrual disturbances; must be taken perfectly & not as effective as combo contraceptives
What is the MOA of estrogen (Premarin)?
Inhibits GnRH from hypothalamus, reducing FSH & LH surges that cause menopause symptoms
Adverse effects of estrogen in menopause
Increased risk of stroke & venous thrombosis in women 50-79, risk of cardiovascular disorders, dementia, & endometrial cancer
What is Danazol used for? (Danocrine)
endometriosis, was once used for macular edema
What is the MOA of danazol in endometriosis? *
lowers estrogen production, inhibits hypothalamus, pituitary GnRH of FSH & LH; Causes atrophy of normal & ectopic endometrial tissue relieving symptoms
What are the ocular side effects of Danazol?
Thromboembolism and papilledema (from idiopathic intracranial hypertension)
What are the androgen and anti-estrogen side effects of danazol?
Male-like side effects: Hirsutism, weight gain, deep voice, & acne.
Hot flashes, flushing, sweating; nausea, headaches & muscle cramps
What are the 4 types of insulin?
- Rapid acting, 2. Short acting (regular) 3. Long acting (NPH), and 4. Ultra long-acting
What are the adverse effects of biguanide (metformin)?
nutritional optic atrophy/pallor, anemias; B12 deficiency, diarrhea, flatulence; risk for lactic acidosis in renal disease (decreases body pH, can be fatal)
Why is metformin the 1st-line therapy for Type 2 DM?
it is the most effective, inexpensive, and does not cause hypoglycemia
What are common side effects of SGL2 inhibitors (Canagliflozin & empagliflozin)?
dry eyes from dehydration, weight loss & reduced blood pressure, acute kidney injury, and genito-urinary fungal/yeast infections
What is the MOA of SGLT2 inhibitors (canagliflozin and empagliflozin)?
Inhibit SGLT2 in proximal renal tubule to prevent glucose reabsorption & increase urinary glucose excretion
Name (2) GLP-1 receptor agonists
Hint: suffix -tide; SC injections
dulaglutide (Trulicity) and exenatide (Byetta)
What is the MOA of GLP-1 receptor agonists (dulaglutide & exenatide)?
stimulate glucose dependent insulin release from pancreas
What is GLP-1?
A glucagon-like peptide; normally produced in gut that stimulates glucose release in pancreas
What are side effects of GLP-1 agonists, (dulaglutide & exenatide)
Weight loss, pancreatitis, & risk of medullary thyroid cancer (in animals)
What is the MOA of DPP4 inhibitors (sitagliptin & linagliptin)?
Inhibit DPP4 (dipeptidyl peptidase 4, which normally inactivates GLP-1) to stimulate glucose dependent insulin release from pancreas
Side affects of DPP4 inhibitors (sitagliptin & linagliptin)?
pancreatitis & joint pain, myalgias
