Drugs acting on the kidney

Question 1

Which transporter do loop diuretics act on?

Answer 1

Na+/K+/2Cl-

Question 2

Where do loop diuretics act?

Answer 2

thick ascending limb of the loop of henle

Question 3

What are 2 examples of loop diuretics?

Answer 3

Furosemide

Bumetanide

Question 4

Where do thiazide diuretics act?

Answer 4

Distal convuluted tubule

Question 5

What transporter do thiazide diuretics act on?

Answer 5

Inhibit the Na+/Cl- co transporter

Question 6

What are 2 examples of thiazide diuretics?

Answer 6

bendrofluethiazide, indapimide, metolazone

Question 7

Where to potassium sparing diuretics act?

Answer 7

Collecting tubules

Question 8

Where do the hormones aldosterone and vasopressin/ADH act?

Answer 8

collecting tubules

Question 9

What does the hormone aldosterone do?

Answer 9

up regulates the activity of Na+/K+ pumps in the collecting ducts and distal convulted tubule.
This results in the reabsorption of Na+ into the plasma and the secretion of K+ into the urine.

Question 10

What is the mechanism of the potassium sparing diuretics?

Answer 10

Inhibits action of aldosterone on the Na+/K+ in the collecting tubules. Prevents the secretion of K+ and the reabsorption of Na+.

Question 11

What do diuretics achieve?

Answer 11

Lower plasma levels of Na+ (hyponatraemia)

Promote diuresis and therefore lower BP

Question 12

What are 2 potassium sparing diuretics?

Answer 12

spironolactone, eplerenone, Amiloride

Question 13

What are the two main concerns with potassium sparing diuretics?

Answer 13

Gynaecomastia (anti androgenic effect)

Hyperkalaemia leading to metabolic acidosis

Question 14

Which substance is 100% absorbed in the kidneys in a normal healthy person?

Answer 14

glucose

Question 15

Where is glucose and amino acids reabsorbed?

Answer 15

proximal convulted tubule

Question 16

How is urine acidified?

Answer 16

Acidification mainly takes place in the collecting tubule and this is via the secretion of H+ and K+ ions into the urine.

Question 17

Where do carbonic anyhydrase inhibitors act?

Answer 17

proximal convuluted tubule

Question 18

What is the mechanism of carbonic anyhydrase inhiitors?

Answer 18

block the reaction of carbon dioxide and water to H+.
This prevents Na+/H+ exchange in the proximal convuluted tubule.
This lowers Na+ reabsorption (as Na+ is usually reabsorbed in order to secrete H+)

Question 19

How do osmotic diuretics work?

Answer 19

The remain in the tubule as they are freely filtered at the glomerulus but poorly reabsorbed. This pulls water to be reabsorbed.

Question 20

In which part of the kidney is sodium reabsorbed the most?

Answer 20

Proximal convulted tubule (65%), Loop of henle (25%),

Question 21

How does vasopressin/ADH regulate water?

Answer 21

V2 stimulation leads to vesicles containing water channels bind to the membranes of cells in the collecting duct cells.
This leads to the reabsorption of water.
V1 receptor stimulation results in vasoconstriction, therefore lowering the amount of plasma filtered.
V1 also enhances the action of aldosterone