Diuretics And Ace Inhibitors

Front 1

type of diuretics (3)

Back 1

1. Loop diuretics (furosemide)
2. Thiazide diuretics (hydrochlorothiazide)
3. Potassium-sparing diuretics

Front 2

1. what are the prototypes of loop diuretics? (2)
2. onset/duration of action (2)

Back 2

1. frusemide/furosemide, bumetanide
2. fast onset (30 min), short acting 2-3 hrs depending on renal function. Faster action if IV

Front 3

how does loop diuretic act? (3)

Back 3

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

Front 4

- Effects of loop diuretics (5)

Back 4

↑Loss of:
- Na
- Cl
- water loss
- K, H+ loss
- Ca, Mg loss

Front 5

Clinical use of loop diuretics (2)

Back 5

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

Front 6

SE and toxicity of loop diuretics (4)

Back 6

1. electrolyte disturbance
2. hypokalemia, alkalosis
3. hypovolemia
4. hypersensitivity: skin rash [due to furosemide and bumetanide sulfonamide structure]

Front 7

Thiazide diuretics:
1. prototypes (3)
2. duration of action/when we give it (2)
3. where does it act

Back 7

1. hydrochlorothiazide, chlorthalidone, indapamide
2. once a day (Longer acting, chronic use). orally active.
3. early segment of DCT: inhibit Na-Cl cotransporter

Front 8

mechanism of thiazide diuretics (3)

effects (4)

Back 8

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.

Front 9

compare loop and thiazide diuretics

Back 9

thiazide is less potent, and slower, than loop

Front 10

clinical use of thiazide diuretics (3)

Back 10

1. HT
2. reduce oedema
3. chronic kidney stone formation ∵ ↓Ca loss in urine

Front 11

toxicity of thiazide (2)

Back 11

1. hypokalemia, alkalosis
2. hypersensitivity (∵ sulfonamide structure)

Front 12

what are the prototypes of potassium-sparing diuretics (2 types.)

Back 12

1. aldosterone antagonists (spironolactone, eplerenone)

2. renal epithelial Na channel inhibitors (amiloride, triamterene)

~orally effective

Front 13

effects of potassium sparing diuretics
1. (general drug effects) (2)
2. spironolactone
3. amiloride

Back 13

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

Front 14

clinical use of potassium-sparing diuretics (3)

Back 14

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)

Front 15

toxicity of potassium-sparing diuretics (2)

Back 15

1. hyperkalemia

2. Spirololactone: gynecomastia, anti-androgenic effects

Front 16

in terms of electrolyte changes, describe difference between loop diuretics, thiazides and K+ sparing diuretics. (4)

Back 16

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 ↓

Front 17

what drugs act on RAAS process? why do we use it? (3)

Back 17

1. Renin inhibitor
2. ACE inhibitor
3. Angiotensin II receptor antagonist

Front 18

ACE inhibitors
1. examples (6). give 2.
2. properties (2)

Back 18

1. the prils: captopril, enalapril, lisinopril, perindopril, quinapril, ramipril

2.
- orally active
- weak diuretic effect
- vasodilator action

Front 19

effects of ACE inhibitors (2)

Back 19

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]

Front 20

clinical use of ACE inhibitors (2)

Back 20

1. treat HT
2. treat CHF, ↑fluid excretion & ↓constriction

Front 21

SE/toxicity of ACE inhibitors (3)

Back 21

1. dry cough
2. symptomatic hypotension w. initial use
3. hyperkalemia

Front 22

angiotensin II receptor antagonists/blockers (ARBs)
1. prototypes (2)

2. action

3. clinical use (4)

Back 22

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!

Front 23

1. examples of renin inhibitors (2)
2. clinical effects (2)
3. uses

Back 23

1. aliskiren, remikiren

2. block renin:

3. HT. Used w. thiazide diuretics (combo tx)
(clin use in CHF not well established yet)

Front 24

summarize loop/thiazide diuretics (3)

Back 24

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

Front 25

summarize K+ sparing diuretics (2)

Back 25

1. ↓ epithelial Na reabsorption, ↑Na and ↓K excretion

2. acts on collecting duct/tubule

Front 26

summarize combination: loop or thiazide + potassium diuretics (3)

Back 26

1. ↓Na & water reabsorption (↑Na & water excretion)
2. ↓ epithelial Na reabsorption (↑Na & ↓K excretion)
3. Diuretic effect, little hypokalemia