Diuretics Flashcards Preview

MET2 > Diuretics > Flashcards

Flashcards in Diuretics Deck (22):
1

What are diuretics?

Increase water loss from kidneys by decreasing sodium reabsorption at different sites

2

What are the 5 classes of diuretics?

Carbonic anhydrase inhibitors
Thiazide diuretics
Loop diuretics
Potassium sparing diuretic
Osmotic diuretics

3

What is the mechanism of carbonic anhydrase inhibitors?

- work on the PCT
- carbonic anhydrase converts H2CO3 into H2O and CO2 which is absorbed by the PCT
- acts within PCT to transform H2CO3 to H+ and HCO3- and HCO3- is absorbed into blood whilst H+ excreted to restarts process
- therefore CA inhibitors stop reabsorption of bicarbonate

4

When are CA inhibitors used clinically?

Lead to metabolic acidosis
Counteract AMS, HACE, PACE - counter-acts respiratory alkalosis due to hyperventilation
ACETAZOLAMIDE

5

Side effects of CA inhibitors?

- metabolic acidosis
- sedation
- bone marrow suppression

6

What is the mechanism of thiazide like diuretics?

Work on the DCT
- Na/K+ ATPase pump out Na+ and pump in K+
- Na+ and Cl- are reabsorbed from DCT lumen due to conc gradient created
- diuretics BLOCK Na+/Cl- symport transporter decreasing sodium reabsorption as no conc. gradient = diuresis as water will follow sodium into lumen

7

What are the clinical effects of thiazide like diuretics?

Hypertension
Blood volume reduction

8

Side effects of thiazide diuretics

Hypokalemia
Hyponatremia
Hypercalcaemia
Hyperglycaemia

9

Examples of thiazide like diuretics

Bendroflumethiazide
Hydrochlorothiazide

10

What is the mechanism of loop diuretics?

- work on ascending limb of LOH
- inhibits Na/K/2CL co-transporter
- decreases absorption of magnesium and calcium (through inhibiting potassium reabsorption into the cell as co-transporter inhibition prevents conc. gradient forming to allow Na+/K+ ATPase to function for K+ to re-enter the cells)

11

Side effects of loop diuretics?

Hypokalemia as potassium excreted not absorbed
Dehydration
Kidney stones
Deafness
Hypotension

12

Examples of loop diuretics?

Furosemide
Bumetanide

13

What is the mechanism of potassium sparing diuretics?

- act on collecting tubules
- epithelial sodium channel antagonists:
block channels, do not affect potassium channels, increased sodium loss = diuresis

14

What is the clinical use of potassium sparing diuretics?

Heart failure
Hypokalaemia
Cirrhosis

15

Side effects of potassium sparing diuretics

Hyperkalaemia
Hyponatremia

16

What are spironolactone and eplerenone examples of?

Aldosterone antagonists
- upregulate epithelial sodium channels (ENACs)
- decrease sodium reabsorption = diuresis
- K+ not affected

17

What is the clinical use of spironolactone/eplerenone?

Heart failure
Hyperaldosteronism
Hypokalaemia
Cirrhosis

18

What are the side effects of spironolactone/eplerenone?

Hyperkalaemia
Hyponatraemia
Gynecomastia

19

Examples of osmotic diuretics?

Mannitol

20

Mechanism of osmotic diuretics

Any osmotically active molecule is free filtered from glom and not reabsorbed in tubules so sodium/potassium/water all dragged out from interstitial space

21

What is the clinical use of osmotic diuretics?

Cerebral oedema/raised intracranial pressure

22

Side effects of osmotic diuretics

Pulmonary oedema