Diuretics - Potassium-sparing (aldosterone antagonist)

Question 1

What are diuretics?

1 - drugs that increase water, Na+ and Cl- excretion
2 - drugs that decrease water, Na+ and Cl- excretion
3 - drugs that increase water, K+ excretion
4 -drugs that decrease water, K+ excretion

Answer 1

1 - drugs that increase water, Na+ and Cl- excretion

• reduce fluid retention

Question 2

Where in the kidneys is blood filtered to form the filtrate?

1 - efferent arteriole
2 - afferent arteriole
3 - glomerulus
4 - juxtaglomerular

Answer 2

3 - glomerulus

Question 3

Once the filtrate is formed from the glomerulus, what happens to the fluid as it move through the tubules and out of the collecting duct as urine?

1 - only glucose is reabsorbed
2 - Na+ and K+ only are reabsorbed
3 - lots of ions and fluids are reabsorbed

Answer 3

3 - lots of ions and fluids are reabsorbed

• H2O, ions (K+, Na+, Cl-)
• what is left is urine

Question 4

Where are ions mainly re-absorbed in the renal system?

1 - loop of henle
2 - distal convoluted tubule
3 - proximal tubule
4 - collecting duct

Answer 4

3 - proximal tubule

• location of most diuretics actions

Question 5

Water passively follows ion re-absorption in the distal tubules of the renal system, which ion specifically does it follow?

1 - Na+
2 - K+
3 -Cl-
4 - HCO3-

Answer 5

1 - Na+
- due to osmosis (H2O dilutes Na+ in blood)

Question 6

Labels the parts of the renal tubules using the labels below:

1 - loop of henle
2 - distal convoluted tubule
3 - proximal tubule
4 - collecting duct

Answer 6

1 - proximal tubule
2 - loop of henle
3 - distal convoluted tubule
4 - collecting duct

Question 7

In the distal convoluted tubules there are principle and alpha cells. Which of the following transporter is NOT typically present on the principle cells?

1 - Na+/K+ATPase
2 - H+ ATPase
3 - Epithelial Na+ channel
4 - ATP dependent K+ channel

Answer 7

2 - H+ ATPase

• Na+/K+ATPase = moves 2Na+ back into interstitium and then blood
• Epithelial Na+ channel = reabsorbes 1 Na+
• ATP dependent K+ channel = pumps 1 K+ ion into lumen

Question 8

In the distal convoluted tubules there are principle and alpha cells. Which of the following transporter is NOT typically present on the alpha cells?

1 - Na+/K+ATPase
2 - H+ ATPase
3 - Epithelial Na+ channel
4 - H+/K+ ATPase

Answer 8

3 - Epithelial Na+ channel

Question 9

Looking at the image below of the principle and alpha cells located in the distal convoluted cells, which of the following are the functions of the principle cells in a normal functioning kidney?

1 - retain Na+ through the Epithelial Na+ channel
2 - excrete K+ through the ATP dependent K+ pump
3 - reabsorb 3 Na+ into blood and excrete 2 K+ into principle cells through the Na+/K+ ATPase pump
4 - all of the above

Answer 9

4 - all of the above

Question 10

Looking at the image below of the principle and alpha cells located in the distal convoluted cells, which of the following are the functions of the alpha cells in a normal functioning kidney?

1 - retain 1 K+ form lumen and excrete 1 H+ into the lumen through the H+/K+ ATPase
2 - excrete H+ through the ATP dependent H+ pump
3 - reabsorb 3 Na+ into blood and excrete 2 K+ into alpha cells through the Na+/K+ ATPase pump
4 - all of the above

Answer 10

4 - all of the above

Question 11

What is the normal function of aldosterone?

1 - inhibits Na+ reabsorption
2 - inhibits K+ reabsorption
3 -Increases Na+, K+ and H2O reabsorption
4 - decreases Na+, K+ and H20 reabsorption

Answer 11

3 - Increases Na+, K+ and H2O reabsorption

• binds with mineralcorticoid receptors on the intercalated cells in the distal tubules
• aldosterone diffuses into the cell and binds to mineralcorticoid receptor forming complex
• the complex enters nucleus and influences DNA causing upregulation of epithelial Na+ channels

Question 12

Does aldoesterone increase or decrease H+ reabsorption in the distal tubules via the alpha intercalated cells?

Answer 12

• increases secretion into the tubulues
• in exchange a K+ is reabsorbed
• this is important as it ensures there is ample K+ to be exchanged with Na+

Question 13

Which of the following is the core K+ sparing medication that we need to be aware of?

1 - Bumetanide
2 - Furosemide
3 - Spironolactone
4 - Bendroflumethiazide

Answer 13

3 - Spironolactone

Question 14

Spironolactone is the core K+ sparing medication that we need to be aware of. Which 2 locations in the renal tubules does Spironolactone act on?

1 - loop of henle
2 - distal convoluted tubule
3 - proximal tubule
4 - collecting duct

Answer 14

2 - distal convoluted tubule
4 - collecting duct

Question 15

Spironolactone is the core K+ sparing medication that we need to be aware of. Spironolactone acts on the cortical collecting tubules namely the distal convoluted tubule and collecting duct. Specifically, Spironolactone acts on the alpha intercalated and principal cells. What is the main function of the intercalated cells?

1 - reabsorb K+ and remove Na+
2 - reabsorb Na+ and Cl-
3 - reabsorb K+
4 - reabsorb Na+ and remove K+

Answer 15

4 - reabsorb Na+ and remove K+

Question 16

What is the mechanism of actoion of the potassium sparing diuretic spirolactone?

1 - inhibits Na+/K+ ATPase
2 - inhibits Na+/K+/Cl co-transporter
3 - inhibits H+/K+ co-transporter
4 - inhibits aldoserone receptor

Answer 16

4 - inhibits aldoserone receptor

• increase Na+ and H2O excretion
• decrease K+ and H+ excretion

Question 17

Why is the potassium sparing diuretic spirolactone indicated and the 1st line drug in ascites and oedema due to liver cirrhosis?

1 - reduces stress on liver
2 - redcues SVR
3 - increases urine output and therefore reduces fluid retention
4 - decreases portal hypertension

Answer 17

3 - increases urine output and therefore reduces fluid retention

Question 18

Why is the potassium sparing diuretic spirolactone indicated chronic heart failure?

1 - increases SVR
2 - redcues SVR
3 - reduces workload of heart
4 - decreases portal hypertension

Answer 18

3 - reduces workload of heart

Question 19

Does the potassium sparing diuretic spirolactone help in primary hyperaldosterone?

Answer 19

• yes
• it is indicated in this group of patients while they await surgery

Question 20

Which of the following is NOT typically an adverse event of the potassium sparing diuretic spirolactone?

1 - hypernatraemia
2 - hyperkalaemia
3 - gynaecomastia
4 - liver impairmenr and jaundice
5 - Stevens-Johnson syndrome (T-cell mediated hypersensitivity)

Answer 20

1 - hypernatraemia

• gynaecomastia is caused by a decrease in testosterone levels

Question 21

Spirolactone can cause hyperkalaemia, which can lead to cardiac abnormalities. Which of the following does not typically occur on an ECG n patients with hyperkalaemia?

1 - prolongation the PR interval
2 - prolongation the QRS interval
3 - loss of P wave
4 - ST segment elevation

Answer 21

4 - ST segment elevation

Question 22

Spirolactone can cause hyperkalaemia, which inturn does what to the resting membrane potential?

1 - decreases resting membrane potential
2 - increases resting membrane potential
3 - no effect

Answer 22

1 - decreases resting membrane potential
- this essentially means that it is easier for muscles to contract, which can result in muscle pain and fatigue

Question 23

The potassium sparing diuretic spirolactone should be avoided in all of the following EXCEPT:

1 - patients with hyperkalaemia
2 - patients with impaired renal function
3 - patients with renal insufficiency
4 - patients with hepatic encephalopathy

Answer 23

4 - patients with hepatic encephalopathy

Question 24

Is spirolactone ok to use in women who are pregnant or breast feeding?

Answer 24

• no
• should be avoided
• evidence to show it can cross the placenta and appear in breast milk

Question 25

Why should causion be used when prescribing spirolactone alongside ACE-I or ARB?

1 - inhibits RAAS
2 - inhibit K+ reabsortpion
3 - increases K+ retention
4 - lead to dehydration

Answer 25

3 - increases K+ retention
- all can cause hyperkalaemia

Question 26

What is the OD recommended prescription of spirolactone for heart failure?

1 - 100mg
2 - 50mg
3 - 25mg
4 - 2.5mg

Answer 26

3 - 25mg
- can be titirated based on the patients response

Question 27

What is the OD recommended with food prescription of spirolactone for acites due to chronic liver cirrhosis?

1 - 100mg
2 - 50mg
3 - 25mg
4 - 2.5mg

Answer 27

1 - 100mg
- can be titirated based on the patients response