Lecture 8

Question 1

What is an example of a loop diuretic?

Answer 1

Frusemide

Question 2

What is an example of a potassium sparing diuretic?

Answer 2

Spironolactone

Question 3

What is an example of an osmotic diuretic?

Answer 3

Mannitol

Question 4

What it the best drug to use in cases of heart failure?

Answer 4

In cases of cardiovascular problems probably use frusemide. Never use mannitol

Question 5

What is the best drug to use in cases of head trauma where there is inflammation and cerebral oedema?

Answer 5

Use mannitol is cases of head trauma.

Question 6

Describe the mechanism of action of Frusemide:

Answer 6

Frusemide blocks the Na+/K+/2Cl- pump causing increased sodium in urine and subsequent water retention.

Question 7

Why are huge amounts of sodium not lost in use of frusemide?

Answer 7

The distal convoluted tubule tries to reabsorb this Na+ by exchanging it with K+. Hence, some Na+ is saved but more K+ is lost. The K+ is not normally a problem are it is easily replenished.

Question 8

How can frusemide be given?

Answer 8

IV, IM, SC, PO

Question 9

How does spironolactone work and what are the benefits of it when compared to frusemide?

Answer 9

Spironolactone is an aldosterone antagonist and it is used in preference to frusemide when concerned about the volume of potassium loss.

Question 10

How does mannitol work?

Answer 10

Increases plasma osmolality but is also freely filtered by the glomerulus and not absorbed by the nephron. As a result it has an osmotic affect in the kidney by preventing fluid re-absorption.

Question 11

How should mannitol be given?

Answer 11

Should be given as a slow IV infusion over 15-30 minutes.