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Flashcards in Urinary Deck (12):
1

Osmotic diuretics mechanism of action?

6 carbon sugar solution. Are filtered but not reabsorbed. Increase osmotic pressure in filtrate, water moves in, increasing urinary output

2

Example of an osmotic diuretic

Mannitol
A- oral absorption poor, IV admin
D- distributed to ecf
E- excreted unchanged on urine
SE? Fluid overload- don't use with chf of oedema

3

Carbon anhydrase inhibitors mechanism of action?

Work in PCT
inhibits CA enzyme, blocks CO2 reabsorption, decreases H in lumen, reduced NaH exchange- blocks reabsorption of Na and HCO3.
Increases Na and HCO3 excretion- water follows

4

Carbonic anhydrase inhibitor example

Acetazolamide
Side effect, not primarily used
Side effects- increase H+
Don't use with liver disease

5

Loop diuretics mechanism of action

Most common
Works on ascending loop of henle
Inhibits Na K CL cotransporters
No osmotic pressure in ECF, water stays in filtrate
Used to treat oedema

6

Loop diuretic example

Furosemide
Very fast acting
Decrease K- hypokaleamia- bradycardia?

7

Thiazides mechanism of action

Work on DCT
Inhibits Na CL co transporter , before aldosterone is stimulated
Increase Na CL Mg K excretion, water stays with ions in filtrate

8

Thiazide example

Hydrochlorothiazole
Side effects less severe than loop diuretics as they are less potent due to less Na to work with
Used to treat oedema

9

Potassium sparing diuretics mechanism of action

All others reduce K- but these don't.
Aldosterone is inhibited (spironolactone) k stays in blood, Na and Cl stays in filtrate- water follows

10

Potassium sparing diuretic example
(Not spironolactone)

Amiloride
Inhibits NaKATPase
Prevents hypokalaemia
Inhibits aldosterone activity
Na stays infiltrate to be excreted- water stays with
K stays in blood- preventing hypokaleamia

11

Dealing with incontinance

Decrease activity of detrusor- decrease parasymp activity
Muscarinic anatgonists- propantheline

Contract internal sphincter- increase sym activity
Alpha agonist - Phenylpropanalamine

12

Dealing with urine retention

Increase activity of detrusor- parasym activation
Muscarinic agonist- bethanecol

Relax internal sphincter- alpha antagonist- prazosin

Inhibit volunatry externla sphincter
Central? Diazepam
Peripheral? Dantrolene