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26 Cards in this Set
- Front
- Back
type of diuretics (3)
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1. Loop diuretics (furosemide)
2. Thiazide diuretics (hydrochlorothiazide) 3. Potassium-sparing diuretics |
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1. what are the prototypes of loop diuretics? (2)
2. onset/duration of action (2) |
1. frusemide/furosemide, bumetanide
2. fast onset (30 min), short acting 2-3 hrs depending on renal function. Faster action if IV |
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how does loop diuretic act? (3)
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1. Inhibit Na-K-2Cl transporter.
- ↓Na, ↓water reabsorbed [thus ↑urine volume] 2. ↓ reabsorption of Ca & Mg [divalent ions] 3. Na-H antiporter effect - high [Na] in tubule so ↑reabsorption - ↑ K & H+ excretion |
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- Effects of loop diuretics (5)
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↑Loss of:
- Na - Cl - water loss - K, H+ loss - Ca, Mg loss |
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Clinical use of loop diuretics (2)
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1. Oedema
due to CHF & pulmonary HT ↓ fluid accumulation in body, ↓ pressure effectively 2. Hypertension (唔多用: short duration of action) ↓ venous return, ↓ stroke volume, lowers pressure |
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SE and toxicity of loop diuretics (4)
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1. electrolyte disturbance
2. hypokalemia, alkalosis 3. hypovolemia 4. hypersensitivity: skin rash [due to furosemide and bumetanide sulfonamide structure] |
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Thiazide diuretics:
1. prototypes (3) 2. duration of action/when we give it (2) 3. where does it act |
1. hydrochlorothiazide, chlorthalidone, indapamide
2. once a day (Longer acting, chronic use). orally active. 3. early segment of DCT: inhibit Na-Cl cotransporter |
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mechanism of thiazide diuretics (3)
effects (4) |
1. Inhibit NaCl cotransporter in early segment of DCT
↓Na, Cl reabsorption, ↓ reabsorption, ↑ urine volume 2. Stimulate Na/Ca exchanger - ↑ Ca reabsorption from urine (opposite of loop diuretics) 3. Na-H antiporter effect - high [Na] in tubule. ↑Na reabsorption, ↑K&H excretion Net: ↑ Na, Cl, water, K, H+ excretion. ↓ Ca, Mg excretion. |
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compare loop and thiazide diuretics
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thiazide is less potent, and slower, than loop
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clinical use of thiazide diuretics (3)
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1. HT
2. reduce oedema 3. chronic kidney stone formation ∵ ↓Ca loss in urine |
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toxicity of thiazide (2)
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1. hypokalemia, alkalosis
2. hypersensitivity (∵ sulfonamide structure) |
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what are the prototypes of potassium-sparing diuretics (2 types.)
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1. aldosterone antagonists (spironolactone, eplerenone)
2. renal epithelial Na channel inhibitors (amiloride, triamterene) ~orally effective |
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effects of potassium sparing diuretics
1. (general drug effects) (2) 2. spironolactone 3. amiloride |
1. ↑Na loss, ↑urine output, ↓K and H+ excretion
2. Spironolactone - blocks aldosterone receptor - inhibit Na/H antiporter: - ↓Na resorption, ↓K&H excretion 3. Amiloride - blocks epithelial Na channel - ↓Na reabsorption so ↓K&H excretion |
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clinical use of potassium-sparing diuretics (3)
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slower, longer
1. Hyperaldosteronism (HF, cirrhosis, kidney disease) 2. ↓K loss w. loop and thiazide diuretics (fixed combo) - Modurectic: amiloride + hydrochlorothiazide, - Dyazide: triamterene + hydrochlorothiazide 3. spiro & eplerenone may ↓cardiac remodeling (HF) |
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toxicity of potassium-sparing diuretics (2)
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1. hyperkalemia
2. Spirololactone: gynecomastia, anti-androgenic effects |
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in terms of electrolyte changes, describe difference between loop diuretics, thiazides and K+ sparing diuretics. (4)
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1. Na+ excretion (most to least): loop, thiazides, K+
2. K+ excretion: Loop, thiazide↑. K+ sparing ↓ 3. Ca+ excretion: Loop ↑. Thiazides ↓. K+ 冇. 4. H+ excretion: Loop, thiazide↑. K+ sparing ↓ |
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what drugs act on RAAS process? why do we use it? (3)
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1. Renin inhibitor
2. ACE inhibitor 3. Angiotensin II receptor antagonist |
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ACE inhibitors
1. examples (6). give 2. 2. properties (2) |
1. the prils: captopril, enalapril, lisinopril, perindopril, quinapril, ramipril
2. - orally active - weak diuretic effect - vasodilator action |
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effects of ACE inhibitors (2)
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Block ACE,
- ↓angiotensin II & aldosterone, - vasodilatation & weak diuretic effect [angiotensin II is the potent vasoconstricter, converted from inactive angiotensin I by ACE. It ↑aldosterone, ↑sodium & water retention] |
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clinical use of ACE inhibitors (2)
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1. treat HT
2. treat CHF, ↑fluid excretion & ↓constriction |
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SE/toxicity of ACE inhibitors (3)
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1. dry cough
2. symptomatic hypotension w. initial use 3. hyperkalemia |
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angiotensin II receptor antagonists/blockers (ARBs)
1. prototypes (2) 2. action 3. clinical use (4) |
1. 'sartans': losartan, valsartan
2. block angiotensin II RECEPTOR ↓angiotensin II & aldosterone [vasodil, diuretic effect] 3. ~ Hypertension ~ unknown: CHF (heart remodelling). stick to ACE inhibitor ~ use with thiazide diuretics. ~ NO dry cough! |
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1. examples of renin inhibitors (2)
2. clinical effects (2) 3. uses |
1. aliskiren, remikiren
2. block renin: 3. HT. Used w. thiazide diuretics (combo tx) (clin use in CHF not well established yet) |
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summarize loop/thiazide diuretics (3)
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1. ↓Na and water reabsorption (↑Na & water excretion)
2. loop Act on loop of Henle, thiazide acts on DCT. results in ↑K loss in collecting tubule 3. diuretic effects, hypokalemia |
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summarize K+ sparing diuretics (2)
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1. ↓ epithelial Na reabsorption, ↑Na and ↓K excretion
2. acts on collecting duct/tubule |
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summarize combination: loop or thiazide + potassium diuretics (3)
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1. ↓Na & water reabsorption (↑Na & water excretion)
2. ↓ epithelial Na reabsorption (↑Na & ↓K excretion) 3. Diuretic effect, little hypokalemia |