33 clinical use of diuretics

Question 1

virtually all diuretics act by directly or indirectly inhibiting what?

Answer 1

ion transporters located on the lumenal membrane of the nephron

Question 2

Drugs such as furosemide and thiazides act by directly binding to their transporters. However, __________ and _________ drugs do not because they work to indirectly inhibit their transporters?

Answer 2

1) Spironolactone

2) acetazolamide

Question 3

Where do spironolactone and eperenone exert their effects?

Answer 3

From the blood side of the nephron. Note that this is opposite to most other diuretics as they work from the luminal (urine) side.

Question 4

How do diuretics generally get into the urine?

Answer 4

Through organic acid or base transporters in the PCT. Not through the glomerulus!

Question 5

Which diuretics are filtered through the glomerulus?

Answer 5

Osmotic diuretics such as glycerin and mannitol.

Question 6

What is acetazolamide? Where does it work?

Answer 6

a carbonic anhydride inhibitor. It works in the PCT.

Question 7

Do you become acidotic or alkalotic if the carbonic anhydrase enzyme is too severely inhibited?

Answer 7

It causes acidosis because the hydrogens are no longer being pumped out into the lumen to form carbonic acid, resulting in less bicarb being able to enter the cell.

Question 8

Furosemide, bumetanide, and ethacrynic acid are all examples of what?

Answer 8

Loop diuretics

Question 9

In what part of the loop do Loop diuretics work? What do they block?

Answer 9

work in the thick ascending part and block the Na+/K+Cl- symporter.

Question 10

where does metolazone work? what type of diuretic is it?

Answer 10

Functions in the DCT and it is considered to be a thiazide like diuretic.

Question 11

Where do you find the aldosterone receptor?

Answer 11

It is located inside the principal cells that are located in the collecting ducts.

Question 12

Which drugs inhibit ENaC? (2x)

Answer 12

1) Amiloride

2) Triamterene

Question 13

T/F If you have heart disease, you should limit the amount of salt you eat per day to about 2000mg?

Answer 13

TRUE

Question 14

What is one of the largest problems associated with giving a diuretic that acts in the PCT or in the nephron loop?

Answer 14

The TGF (tubuloglomerular feedback system of the macula. It causes a decreased urine flow if it senses too much Na+ in the urine flowing past it.

Question 15

What affect does furosemide have on the osmotic gradient of the renal medulla?

Answer 15

it decreases the medullary osmotic gradient because not as much sodium is being reabsorbed like normal.

Question 16

what affect does furosemide have on capacitance?

Answer 16

it increases venous capacitance resulting in decreased left ventricular filling pressure.

Question 17

Diuretics help the patient by getting rid of extra fluid within cells and around cells (third spacing). What main functions do they have on the lungs?

Answer 17

decrease pulmonary edema
decrease SOBi
ncrease O2 saturation

Question 18

What are the 7 major complications of using furosemide

Answer 18

1) sodium depletion
2) Hypomagnesemia
3) ototoxicity
4) uric acid retention
5) decreased renal perfusion
6) alkalosis
7) Hypokalemia

Question 19

Which diuretic is used to reduce BP, are well tolerated, and are inexpensive?

Answer 19

Thiazide diuretics

Question 20

Early on with diuretic use, the major hypotensive effect is to?

Answer 20

reduce extracellular fluid volume

Question 21

Chronic reduction of BP results mainly from?

Answer 21

reduction in pulmonary vascular resistance (PVR)

Question 22

T/F diuretic based therapy decreases the incidence of CHF in the elderly?

Answer 22

TRUE

Question 23

T/F thiazides decrease Ca+ excretion?

Answer 23

TRUE

Question 24

Diuretics can decrease what?

Answer 24

1) BP
2) PV
3) TPR
4) CO (only initially)

Question 25

Complications of thiazide diuretics include (7)?

Answer 25

volumedepletion
hyponatremia
hypokalemia
hypomagnesemia
hyperlipidemia
hyperuricemia
glucose intolerance

Question 26

Nephrotic syndrome consists of which 3 things?

Answer 26

1) proteinuria
2) hypoalbuminemia
3) edema

Question 27

T/F Patients using diuretics such as thiazides often have high cholesterol?

Answer 27

true because of the hyperlipidemia effect

Question 28

what is the goal behind using an oral diuretic for edema?

Answer 28

to reduce discomfort associated with the edema and not necessarily to eliminate the edema completely.

Question 29

What do you have to change up when the patient you are trying to treat has nephrotic syndrome?

Answer 29

you need a potent diuretic such as a loop diuretic.

Question 30

If you have a patient that has diuretic resistance, what are 5 major things you should think about?

Answer 30

1) incorrect diagnosis
2) non-compliance
3) Inappropriate NaCl intake
4) Inadequate drug reaching tubule
5) decreased renal response

Question 31

If you have decreased renal function and find that the diuretic is not working because of too much uremic toxins, what is the mechanism messing things up?

Answer 31

The uremic toxins are competing with the diuretic for the organic ion transporter in the PCT.

Question 32

Decreased activation of RAA axis, NSAIDS, low GFR, and nephron adaptation all result in what?

Answer 32

decreased renal response to diuretics

Question 33

If you find that your loop diuretic is not working properly and you have eliminated most other potential problems such as lack of compliance, what should you do to help treat a patients edema?

Answer 33

Give them a diuretic such as thiazide or ENaC inhibitor. This is helpful because there do not deal with the TGF feedback system

Question 34

Patients with cirrhosis generally have what?

Answer 34

secondary hyperaldosteronism which causes increased distal Na+ absorption.

Question 35

T/F although loop diuretics are potent, due to the hyperaldosteronism, the excess sodium delivered to the distal tubule in reclaimed?

Answer 35

TRUE

Question 36

What do spironolactone and eplerenone do?

Answer 36

aldosterone antagonists.

Question 37

What side effects can the two aldosterone antagonists have?

Answer 37

1) hyperkalemia
2) Gynecomastia (Spironolactone)
3) agranulocytosis (Spironolactone)
4) hyponatremia

Question 38

What is Lasix?

Answer 38

Furosemide

Question 39

T/F most loop diuretics are long lasting?

Answer 39

false, they are short lasting.

Question 40

uremic toxins compete with _______ for the organic ion transporter?

Answer 40

diuretics

Question 41

If you have a loop diuretic that doesnt seem to be working well, what 2 things should you try?

Answer 41

1) increase dose to 2x daily

2) add a thiazide diuretic

Question 42

Ototoxicity is associated with?

Answer 42

All loop diuretics but especially furosemide.

Question 43

Furosemide can have major complications that include (5)?

Answer 43

sodium depletion
ototoxicity
alkalosis
uric acid retention
hypocalcemia.