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Flashcards in Endocrine 1, 2 Deck (87):

Insulin MOA

Insulin binds to plasma membrane receptors initiating an intracellular cascade of enzymatic events: Glucose diffusion into cells, glucose storage mode, uptake of AA/phos/K/mg, protein synthesis, inhibition of proteolysis, fatty acid/TG synthesis, dec lipolysis, regulate DNA/ gene expression (via insulin regulatory elements)


___ units of physiologic insulin is the average daily requirement

40 units


In what way does ANS control insulin release?

Alpha decreases insulin secretion
Beta and PSNS increases insulin secretion


Which insulins are mixed commonly?

R/NPH or rapid/NPH
Before breakfast, R covers breakfast, NPH covers lunch (or R dinner; NPH night)


Which types of insulin are ultra-rapid acting? Onset, peak, DOA?

Lispro (humalog)
Aspart (novolog)
Glulisine (apidra)
Onset 15-30 min, peak 30-60 min, DOA 3-5h


Which types of insulin are short acting? Onset? Peak? DOA?

Regular (humulin R, novolin R)
Onset 30 min (slight peak of glucose before insulin starts working)
Peak 1-5h, DOA 5-8h


Which types of insulin are intermediate acting? Onset? Peak? DOA?

NPH (humulin N, novolin N)
P=protamine (this is what we use to reverse heparin), they may develop protamine allergy over time
Onset 1-2h, peak 6-10h, DOA 16-20h


Which types of insulin are long-acting? Onset, peak, DOA?

Glargine (lantus)- no peak, not mixed with other insulins
Detemir (levemir)
Stimulate basal release (no peak)
Onset 2-6h, DOA 24h


IV regular insulin pharmacokinetics? E1/2t, DOA, metabolism

E1/2t 5-10 min
DOA 30-60 min
Proteolytic enzyme metabolizes insulin in the liver and kidneys


Insulin adverse reactions?

Injection site reaction
Lipodystrophy at site
Protamine allergy (only NPH)
Weight gain


Hypoglycemia symptoms?

Diaphoresis, tachycardia, hypertension (epi response to raise BG), CNS agitation, seizures, coma


Drug interactions with insulin?

ACTH, glucagon, estrogens- oppose hypoglycemic effects
Epi decreases release of insulin (raises BG)
Tetracycline, chloramphenicol, salicylates- prolong DOA
MAOIs increase hypoglycemic effects


In type 1 DM, 1 unit insulin decreases BG by ____
In type 2 DM 1 unit insulin decreases BG by ____

Type 1: 40-50 mg/dL
Type 2: 30-40 mg/dL
Although it varies with individuals


Benefits of tight controlled BG vs. non-tight control?

Tight control: reduces risk of chronic complications in type 1 DM, also inc wound healing, dec infection, dec osmotic diuresis, dec DKA incidence
Non-tight control: when controlled to tightly, we risk hypotension, plus its annoying and more work


Hyperkalemia treatment

10u Reg insulin IV
25g glucose, 1 amp 50% dextrose in 5 min


Hypoglycemia treatment

OJ, soda, honey, sugar tablet/cube
25-50 mL 50% dextrose solution


Which of these oral antidiabetic medications cause hypoglycemia?
Sulfonylureas, biguanides, thiazolidinediones, alpha-glucosidase inhibitors, melitinides, GLP-1 mimetics/gliptons

Can cause hypoglycemia: Sulfonylureas, gliptons, and meglitinides all increase insulin secretion from B cells
Don't cause hypoglycemia: biguanides and TZDs increase insulin sensitivity at target tissues, alpha-glucosidase inhibitors slow absorption from the gut


Sulfonylureas MOA?

Stimulate release of insulin from pancreatic beta cells
Binds to ATP sensitive K channes in the cell membrane resultinmg in depolarization, Ca influx, and insulin release (tricks the beta cell into thinking it is in a glucose-rich state)
Secondary MOA: enhance beta cell sensitivity to glucose, enhance tissue sensitivity to insulin, lower BG


Sulfonylureas effect on FBG and Hbg A1C?

Reduce FBG 60-70 mg/dL
Reduce Hgb A1C 2%


List 1st and 2nd generation sulfonylreas and their DOA

1st: Tolbutamine (orinase) DOA 6-12h; chlorpropamide (diabinese) DOA 36-72h
2nd: glipizide (glucotrol) DOA 12-24h; glymuride (micronase, diabeta) DOA 18-24h; glimepiride (amaryl)
1st gen has more drug interactions and SE than 2nd bc 2nd gen is 100x more potent


Sulfonylureas pharmacokinetics?

90-98% protein bound
Metabolized hepatically (avoid in liver dz), some active metabolizes
If renal impairment, use glipizide or tolbutamide


Sulfonylureas adverse effects?

HYPOGLYCEMIA (hold 1-2 days preop)
GI: N/V, fullness, heartburn, cholestasis, altered LFTs, appetite stimulant (exacerbate obesity)
GU: ADH effect- Na and H2O retention
Pruritis, rash


Biguanides: MOA

Dec hepatic and renal glucose production (decreased gluconeogenesis/glycogenolysis), inhibits aerobic metabolism


Biguanides benefits

No weight gain, possible weight loss
May increase HDL, decrease LDLs and TGs
Hypoglycemia rare when used alone


Biguanides adverse effects

GI distress (diarrhea, metallic taste, nausea)
Lactic Acidosis
Hold 1-2 days before surgery


Biguanides contraindications

Women with ESRD, creatinine over 1.4
Med with ESRD, creatinine over 1.5
Hepatic dysfunction
CHF, shock, hypoxic pulmonary disease


Thiazolidinediones (TZDs): MOA, and name a couple?

Improves insulin sensitivity/decreases insulin resistance peripherally
Pioglitazone (Actos)
Rosiglitazone (Avandia)


TZDs clinical effect and pharmacokinetics?

Effect: decreases FPG up to 50 mg/dL, decreases Hgb A1C 1-2%, resumes ovulation in premenopausal women who have insulin resistance
PO, hepatic metabolism


Alpha-gucosidase inhibitors MOA and name a couple of them

MOA: competitively and reversibly antagonizes enzymes in the intestinal brush border responsible for digesting complex carbohydrates (when in the GI tract, it doesn't get reabsorbed to the blood) delays glucose absorption, lowers post-prandial hyperglycemia (after a meal)
Acarbose (precose)
Miglitol (glyset)


TZD side effects and black box warning?

SE: edema, weight gain, hepatotoxicity (monitor LFTs, look for jaundice)
Black ox warning: CHF (can cause or exacerbate), MI (from rosiglitazone)


Alpha-glucosidase inhibitors clinical effect and pharmacokinetics?

Decreases PPG 60-70
Decreases FBG 25-30 only
Decreases Hbg A1C 0.7-0.9%
Not absorbed after oral administration, excreted in stool


Alpha-glucosidase inhibitors adverse effects? Cautions?

Abdominal pain/distention, diarrhea, flatulence
Caution in patients with IBD, ulcers, intestinal obstruction
Tak with first bite of meal, if you skip a meal, skip the dose


Meglitinides MOA, how do they compare to sulfonylureas?

MOA: stimulates insulin secretion from pancreatic beta cells, quick onset and peak (1h), short DOA (4h), reduces PPH (postprandial hyperglycemia)
Compared to sulfonylureas, less hypoglycemia, shorter DOA, quicker onset


Name a couple meglitinides, what are adverse effects?

Repaglinide (prandin), nateglinide (starlix)
AE similar to sulfonylureas, hypoglycemia, n/v/c/d, heartburn, headache
Take it 15-30 min before meals, if a meal is skipped, skip the dose


GLP-1 Agonisits (gliptins) MOA

Inhibits DPP4 (an enzyme that inactivates uncertain hormones, GLP1), enhances glucose-dependent insulin secretion, reduces glucagon secretion, slows gastric emptying


Sitagliptan (januvia)- what are the beneficial effects and adverse effects? E1/2t?

E1/2t 12h
Reduces postprandial and fasting BG
AE: rare fatal pancreatitis and anaphylaxis


What is exenatide (byetta)?

Synthetic GLP1, mimics GLP1 (an incretin), similar to gliptin, used as an adjunct to metformin or sulfonylureas


Exenatide (byetta) adverse effects?

N/V, delayed gastric emptying
Renal failure, pancreatitis
Antibodies developed against the drug


Pramlintide- what is it?

Amylin mimetics
Amylin is a pancreatic hormone released with insulin


Pramlintide (amylin mimetic): effects? Uses?

Reduces postprandial blood glucose
Used in both DM 1 and 2 who fail to attain control with insulin


Pramlintide pharmacokinetics? AE? Interactions?

Peaks in 20 min, E1/2t 50 min
Metabolized in the kidney (NOT liver)
AE: high risk for hypoglycemia, nausea, injection site reaction
Interactions: decreased absorption of ABX an oral contraceptives


What does the thyroid do?

Responsible for growth and development of nervous system in infants
Regulates metabolism and body temp
Synthesizes and secretes thyroid hormones and calcitonin


Thyroid hormones are made up of two tyrosine molecules that are ____ and linked by an _____

They are IODINATED. Iodine is an essential component of thyroid hormones.
Linked by an ether


_____ releases thyrotropin-releasing hormone (TRH). THR causes release of TSH from the ____

Hypothalamus releases TRH
Anterior pituitary releases TSH


Does the thyroid secrete more T3 or T4?

T4, which is then converted into T3 in the periphery


What do anti-thyroid drugs do? Name a couple.

Tx hyperthyroidism/ Graves
Ex: propylthiouracil (PTU), methimazole
Blocks organification process by competing with thyroglobulin for oxidized iodide
Reduces synthesis of thyroid hormones


Antithyroid drugs onset of action?
PTU, methimazole

1-2 weeks


Is methimazole or PTU more potent, causing less side effects?

Methimazole is more potent, only requires daily dosing, less side effects


Antithyroid drugs adverse effects?

Goiter formation (inhibition of thyroid hormone up regulates TSH, leading to thyroid gland hypertrophy)
PTU only- dec prothrombin, causes bleeding
Pruritic rash
Rare: agranulocytosis, hepatotoxicity, vasculitis


Other things that PTU does

Inhibits conversion of T4 to T3 in the periphery
Increased bleeding tendency
Preferred in pregnancy, doesn't cross placenta
Preferred in thyroid storm (acute hyperthyroidism)


What other meds treat hyperthyroid?

B-blocker: blocks hyperadrenergic effects (tachycardia, tremor, nervousness), use esmolol for thyroid storm
Corticosteroids: suppresses thyroid receptor Ab and inflammation
Iodide: blocks conversion of T4 to T3, decreases vascularity of thyroid gland, blocks thyroid hormone release (this is only temporary treatment)


What other treatments besides meds for hyperthyroid?

Radioactive iodine, thyroid gland ablation
Surgical removal of thyroid gland
These options usually require thyroid replacement


Levothyroxine (synthroid): what is it?

Tx hypothyroid
Chemically synthesized T4


Levothyroxine half-life? What needs to be monitored?

LONG half-life of 7 days
Easy to titrate
Monitor TSH, T4, and s/s of hyperthyroid if dose is too high
Monitor for adverse reaction: rash


When would you give T3 liothyronine (cytomel) instead of T4?

Life-threatening hypothyroidism, myxedema coma
Otherwise give T4- levothyroxine


Levothyroxine drug interactions?

Inc levothyroxine metabolism- penobarbital, phenytoin, rifampin, carbamazepine
Dec T4-T3 conversion- PTU, b-blockers, amiodarone, glucocorticoids
Dec absorption from gut- cholestyramine, FeSO4, AlOH3, sucralfate, kayexelate
Inc thyroid binding- pregnancy, estrogen


Name 3 drugs that alter thyroid status

Amiodarone: structure resembles thyroid hormone, can cause hyper/hypo-thyroid
Lithium: body thinks its iodine, leads to hypothyroidism
Metoclopramide: increases TSH


Corticosteroids: what are mineralocorticoid effects vs. glucocorticoid effects?

Mineralocorticoid effects: reabsorption of Na and secretion of K in renal distal tubule (aldosterone effects)
Glucocorticoid: antiinflammatory, augmentation of SNS activity


Corticosteroid MOA

Bind to steroid receptors in the cytoplasm
Note: Mineralocorticoid receptors are found in organs of excretion, glucocorticoids wide-spread
Steroid enters nucleus and influences DNA transcription (enhances/inhibits)


Corticosteroid effects

Raises BG, amino acid, TGs
Inflammatory response inhibited (arachidonic acid pathway)


Cortisol (solu-cortef) pharmacokinetics?

90% protein bound
Metabolized mostly in liver, the rest is eliminated unchanged in the urine
E1/2t 1.5-3h


How much endogenous cortisol do we secrete per day?

50-150mg with extreme stress


Which steroid, when given with zofran before surgery, has a synergist long term effect on reducing post-op nausea?

Dexamethasone (decadron)
DOA is very long, 36-54 hours


Methylprednisolone, betamethasone, and prednisolone: do they have mineralocorticoid or glucocorticoid effects?

Methylprednisolone: glucocorticoid effects
Betamethasone: lacks mineralocorticoid effects
Prednisolone: both effects


Corticosteroids big clinical uses?

Adrenal insufficiency: cortisol
Allergy/asthma: glucocorticoids, but takes 4-6h to see antiinflammatory effects
Antiemetic: Decadron


If you swallow the inhaled glucocorticoid what are you risking?

Dysphonia- laryngeal muscle myopathy


Corticosteroids 3 big clinical uses?

Adrenal insufficiency: cortisol
Allergy/asthma: glucocorticoids, but takes 4-6h to see antiinflammatory effects
Antiemetic: Decadron 8-10mg, inhibits COX resulting in post-op analgesic effect


Other clinical uses for corticosteroids? (besides adrenal insufficiency, allergy, antiemetic)

Intracranial tumors
Aspiration pneumonitis
Immunosuppression (transplant)
Lumbar disc herniation (triamcinolone/methylprednisolone epidural injection)
RA, SLE, MG, sarcoidosis, ocular/cutanous inflammation
UC, RDS prevention, leukemia


Corticosteroid side effects/interactions

HPA suppression (CV collapse)
Fluid/electrolyte imbalance, CBC changes
Infection, ulcers
Osteoporosis, skeletal muscle weakness
Psych disorders, growth retardation, dec anticoagulant effectiveness


Glucagon: what is it and what releases it?

Polypeptide hormone, produced by alpha cells in pancreas in response to hypoglycemia, an antagonist to insulin that raises BG


Glucagon MOA

Enhances cAMP (inc myocardial contractility, HR, gastric motility, renal flow, insulin secretion, gluconeogensis/glycogenolysis, relaxes smooth muscle, dec gastric motility)


Glucagon clinical uses

Increased CO (helps with b-blocker OD, improves CHF)
Biliary dilation (helps with biliary stent placement)
Enhance AV node conduction, diagnose pheo


Glucagon clinical uses? dose?

Increased CO (helps with b-blocker OD, improves CHF)
Biliary dilation (helps with biliary stent placement)
Enhance AV node conduction, diagnose pheo
1-5mg IV or 5 mcg/kg/min (20 mg/h)


Glucagon side effects

Inc HR (esp. with Afib pts)


Somatostatin is a GI regulatory peptide secreted by _____

pancreatic delta cells


Octreotide/ somatostatin

Octreotide is a SS analogue, both inhibit production and release of hormones from the GI tract and pancreas (inhibit growth hormone release, insulin secretion, and glucagon release)


E1/2t differences between SS and octreotide?

SS E1/2t 3 min
Octreotide E1/2t 2.5h


Octreotide uses?

Carcinoid crisis (dec release of amines like serotonin, but watch out for HB/bradycardia)
Hepatorenal syndrome
Control of esophageal variceal bleeding


Vasopressin/ADH: what happens at V1 and V2 receptors?

V1: arterial smooth muscle vasocontriction
V2: inc water permeability/reabsorption at the collecting ducts in nephron back into circulation (reabsorbs more water)


Vasopressin uses? E1/2t?

Diabetes insipidus
Esophageal varices r/t hemorrhage
Hemorrhagic/septic shock
Cardiac arrest resuscitation instead of epi
E1/2t 10-20 min


Vasopressin side effects

Increased BP
Coronary artery vasoconstriction: MI, angina
GI hyperperistalsis: N/V, abd pain


Vasopressin/ADH: what happens at V1 and V2 receptors?

V1: arterial smooth muscle vasocontriction
V2: inc water permeability/reabsorption at the collecting ducts in nephron back into circulation (antidiuretic!)


How does dosmopressin (DDAVP) compare to vasopressin?

DDAVP has a longer E1/2 of 2.5-4.4 hours
More selective for V2 receptors (antidiuretic)
Better choice for DI
Stimulates secretion of vWF


Oxytocin (ptosin): what is it used for and what does it do?

Causes uterus contraction: induces labor, inc uterine tone after C-section, dec postpartum hemorrhage
High doses dec BP


Oral contraceptives are a combo of what drugs to inhibit ovulation?



Estrogen prevents release of ____
Progesterone prevents release of ____

Estrogen prevents release of FSH
Progesterone prevents release of LH


Oral contraceptive side effects?

Thromboembolism: DVT