Endocrine Disorders Flashcards
Thyroid gland active hormones (2)
Triiodothyronine (T3)
Thyroxine (T4)
Actions of thyroid hormones
- stimulation of energy use -> calorigenic
- stimulation of heart: increase HR, increase blood flow
- promote growth and development
Levothyroxine
[synthroid, many brands]
synthetic prep of T4
- converted to T3
- highly protein bound -> t1/2 = 7 days
Liothyronine
[Cytomel]
synthetic prep of T3
- more ptoent but shortr t1/2
- higher cost
- increased dcardiotoxicity
Thyroid hormones AE
with significant overdosage -> thyrotoxicosis
- tachycardia, tremors, nervousness, insomnia
BBW: ineffective and potentially dangerous for treatment of obesity/weight loss in euthyroid patients -> life-threatening toxic effects
Methimazole [Tapazole]
uses: hyperthyroidism
MOA: suppression of thyroid hormone synthesis
- longer t1/2 -> once daily with preferred side effect profile
Propylthiouracil (PTU)
uses: hyperthyroidism
MOA: suppression of thyroid hormone synthesis
- short t1/2 -> needs to be administered several times/day
Beta blockers (3) -ol
Propranolol
metoprolol
atenolol
uses: hyperthyroidism
MOA: suppress tachycardia and other symptoms
Radioactive iodine [I131]
uses: hyperthyroidism
MOA: destroy thyroid tissue in patients with hyperthyroidism
- safe and effective but hypothyroidism occurs 80%
- 1st choice in elderly and post menopause with persistent nodules
Non-radioactive iodine [lugol’s solution]
uses: hyperthyroidism
MOA: at high concentrations, iodide has a suppressant effect on the thyroid
Hormones of anterior pituitary (6)`
growth hormone (GH)
follicle-stimulation hormone (FSH)
luteinizing hormone (LH)
thyrotropin (TSH)
prolactin
corticotropin, adrenocorticotropic hormone (ACTH)
Hormones of the posterior pituitary (2)
oxytocin
antidiuretic hormone
Growth hormone aka somatropin [Saizen]
Biologic effects:
- Promotes growth, protein synthesis, and carbohydrate metabolism
Therapeutic uses: IM or SubQ
- Pediatric GH deficiency
- Pediatric non-GH deficient (NGHD) short stature
- Adult GH deficiency → increases lean body mass
Growth hormone aka somatropin [Saizen] abuse
Abuse → DOPING w/hGH has become an increasing problem in sports during the last 15yrs
Prolactin
produced by the anterior pituitary
- stimulation of milk production after parturition
Cabergoline [Dostinex]
a dopamine agonist
- for suppression of prolactin release
Oxytocin
- promotes uterine contractions during labor
- stimulates milk ejection during breast feeding
- induction of labor near term
Antidiuretic hormone (ADH) aka vasopression
ADH promotes renal conservation of water
Desmopressin: diabetes insipidus, primary nocturnal enuresis (bedwetting, urination while sleeping)
vasopressin: vasopressor- shock
Adrenocorticol hormones (steroid hormones) (3)
glucocorticoids (cortisol)
mineralocorticoids (aldosterone)
androgens (androstenedione)
Glucocorticoids uses
- Adrenocortical insufficiency → Addison’s disease
- Non-adrenal disorders
Nonadrenal disorders
- Allergic conditions
- Asthma
- Dermatologic disorders (eczema, psoriasis)
- Miscellaneous inflammatory disorders (e.g., tendinitis, bursitis, osteoarthritis, gouty arthritis)
- CA arising from lymphoid tissues (leukemia, Hodgkin’s disease) in conjunction w/antiCA drugs
- Suppression of allograft rejection in conjunction w/other immunosuppressive agents
- Autoimmune diseases: RA, systemic lupus erythematosus (SLE)
- Inflammatory bowel disease
Steroid receptor complex
MOA: glucocorticoids binds to intranucler receptors -> complex activates transcription of certain genes
Corticosteroid Clinical Considerations
- Therapeutic use, usually empirical
- Nonspecific and palliative, not curative
- Adrenal suppression by negative feedback regulation during long term therapy.
- Avoid abrupt cessation -> Glucocorticoid withdrawal should be done slowly when given for > one month
- Intermittent dosage used when possible
- Use smallest dose for desired effect
- Administered before 9:00 AM to avoid adrenal insufficiency and mimic the burst of endogenous release
- During long term therapy, higher dose should be given at time of stress
Glucocorticoid withdrawal
- Depend on signs of adrenal suppression
- Taper the dosage to physiologic range over 7 days
- Taper the dosage to 50% of physiological values over the next months
- Switch from multiple Doses to single dose
- Monitor for production of endogenous cortisol -> cease replacement therapy when basal levels return to normal
Glucocorticoids AE
Adrenal insufficiency
Susceptibility to infection
Osteoporosis
Hyperglycemia and glucosuria
Weight gain
Fluid and electrolyte disturbance, edema, hypokalemia
Cataracts and glaucoma
Peptic ulcers by inhibiting PG synthesis
Growth retardation in children
CNS effects, nervousness, insomnia, depression, euphoria
Cushing syndrome
Hydrocortisone [Cortef]
short to medium acting/low GC potency
Prednisone [Deltasone]
For oral anti-inflammatory and immunosuppressant
- prednisone is a prodrug → chemically changes in body after it is swallowed → turns into active form, prednisolone*
Methylprednisone [Medrol]
PO: more potent than prednisone
Dexamethasone [Dex Pax]
long acting GC/potent GC
- potent anti-inflammatory
9- alphafludrocortisone [Florinef]
MOA: binds to aldosterone receptor -> mineralocorticoid property and glucocorticoid activity
uses: addison’s disease, adrenogenital disorder
AE: edema, hyperglycemia decrease body growth
Mifepristone [Korlyn]
MOA: cortisol receptor blocker at high dose, at low dose it is a progesterone receptor blockers
-> inhibition of progesterone during pregnancy, causing expulsion of product of conception through contraction
uses: tx for hyperglycemia secodary to hypercortisolism
-mifepristone + misoprostol -> abortion < 40 days of pregnancy
AE: abnormal bleeding, HTN, edema
