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41 Cards in this Set
- Front
- Back
What is the purpose of diuretics?
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Increase the rate of urine flow and increase the rate of Na+ excretion usually as NaCl
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What are some examples of cardiovascular diuretics?
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digitalis (digoxin), phosphodiesterase inhibitors (aminophylline, inamrinone, milrinone)q
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What is the clinical use of cardiovascular diuretics?
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Treatment of edema associated with congestive heart failure
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Physological diuretics include:
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water and NaCl
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What effect does additional water have on the body?
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Inhibits the release of ADH
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What is the clinical use of water as a physiological diuretic?
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used in compensated chronic interstitial nephritis of dogs
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When is NaCl used as a physiological diuretic
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in sheep, calves, and cats with urolithiasis
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What are some examples of osmotic diuretics?
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mannitol, urea, glycerin, isosorbide
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What is the mechanism of action for osmotic diuretics?
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acts at the loop of henle and PCT to interefere with transport mechanisms and increase urinary excretion of metabolites thereby decreasing medullary tonicity.
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What are the clinical uses of osmotic diuretics?
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local edema only: cerebral edema, acute glaucoma, acute renal failure, mobilized edema fluid, drug overdose
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What are some examples of a loop or high ceiling diuretic?
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furosemide, bumetanide, ethacrynic acid
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What is the mechanism of action of drugs like furosemide?
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inihibits the Na/K/2Cl- symporter and paracellular reabsorption of Na, Ca, Mg
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Which class of diuretics is the most efficacious and why?
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Loop Diuretics are the most efficacious because ~25% of filtered Na+ is reabsorbed at the ascending loop
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How does hypokalemia and thus systemic alkalosis develop with administration of loop diuretics?
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Hypokalemia and resultant systemic alkalosis is caused by the increased delivery of Na+ in the distal tubule and collecting duct. This increases the potential difference of the membrane and facilitates K+ excretion through K+ channels in luminal membrane of the principle cells. There are also H+ secretion by intercalated cells into the lumen. RAAS stimulation also contributes.
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What are the therapeutic uses for loop diuretics like furosemide?
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acute pulmonary edema, pulmonary congestion, generalized edema associated iwth congestive heart failure, chronic renal failure, and liver cirrhosis.
increased intracranial pressure and udder edema, exercise induced pulmonary hemorrhage in horses |
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Which class of diuretics is used to tx exercise induced pulmonary hemorrhage in horses?
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loop diuretics- furosemide
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Which class of diuretics would be used to threat life-threathening hyponatremia in conjuction with hypertonic saline?
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loop diuretics because they inhibit the kidney from producing concentrated urine
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What are some adverse effects of loop diuretics?
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ototoxicity, hypokalemia, hypomagnesemia, acute hypovolemia, hypotension, cardiac arrhythmia, hyperglycemia, hyperuricemia, systemic alkalosis, hypersensitivity
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What are the pharmacokinetics of furosemide?
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orally or IV
onset is rapid, duration is short |
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What are some examples of thiazide diuretics?
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hydrochlorothiazide, chlorothiazide
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What is the mechanisms of action for thiazide diuretics?
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inhibit the Na+-Cl= symporter in DCT- inhibits tubular reabsorption of Na/Cl
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Compare the efficacy of thiazide diuretics to loop diuretics.
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Thiazide diurectics have a lower efficacy compared with loop diurects because of their site of action. Loop diuretics act on the ascending loop of henle where 25 % of Na is reabsorbed wherease thiazide diuretics work in the DCT where only 5% is reabsorbed
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Which two diuretic classes cause hypokalemia and systemic alkalosis?
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loop diuretics and thiazide diuretics
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What the major clinical uses of thiazide diuretics?
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tx of hypertension, nephrogenic diabetes insipidus, calcium nephrolithiasis, osteoporosis, udder edema,
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What are the adverse effects of thiazide diuretics?
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electrolyte imbalance (hypnatremia, hypokalemia, hypmagnesemia), but less than loop. Hyperglycemia, hypersensitivity reactions in patients allergic to sulfonamides
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What are the pharamcokinestics of thiazide diuretics?
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orally, absorption is slow/incomplete, binds to plasma proteins, excreted in kidneys
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What are some examples of potassium sparing diuretics?
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spironolactone, triamterene, amiloride
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What is the mechanism of action for spironolactone?
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competitively blocks aldosterone resutls in excretion of NaCl and diureses as well as retention of K+ and H+
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Rank the diuretics in terms of efficacy:
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Loop>thiazide>potassium sparing
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What are the therapeutic uses of spironolactone?
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diuretic, treatment of 1 and 2 hyperaldosteronism
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What are the adverse effects of spironolactone?
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hyperkalemia, systemic acidosis, effects reproduction
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What considerations do we have to make for spironolactone?
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it has a slow onset (2-3 days), long duration, only mild diuretic effect
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What is the mechanism of action for the potassium sparing diuretics triamterene and amiloride?
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blocks epithelial Na+ channels in DCT and collecting duct.
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what are the therapeutic uses of triamterene or amiloride?
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treatment of hypokalemia, hypomagnesemia
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What drugs make up the carbonic anhydrase inhibitors?
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acetazolamide, methazolamide, dorzolamide, brinzolamide
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How do Carbonic anhydrase inhibitors work?
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reversible inhibiton of carbonic anydrase which exchanges H for Na at PTC
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Therapeutic uses of carbonic anhydrase inhibitors?
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treatment of chronic glaucoma, udder edema
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Adverse effects of carbonic anhydrase inhibitors:
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mild systemic acidosis, hypokalemia, hyperglycemia
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What is the drug that is used to diagnose Diabetes insipidus?
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ADH helps us differentiate between Central and Nephrogenic DI
If central caused by ADH def and we'll see change, if neprhogenic no response |
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`Which drugs would we use to treat central Diabetes insipidus?
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Desmopressin via nasal drops
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Which drug would we use to treat nephrogenic diabetes insipidus?
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thiazide diuretic
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