9.5 Medications that affect the Kidneys

Question 1

What do diuretics do?

Answer 1

Shift water and solutes from the vascular space to the urine (they don’t simply make you piss)

Question 2

What is the danger of diuretics working too fast?

Answer 2

• Too much fluid leaves the vascular space, can lead to dangerous decreases in renal perfusion rate

Question 3

Basic mech of diuretic action

Answer 3

• Inhibit sodium reabsorption
• More water is obtained in urine

Question 4

List some loop diuretics

Answer 4

• Frusemide
• Bumetanide
• Ethacrynic Acid

Question 5

Where do loop diuretics act?

Answer 5

Luminal Na+/K+/Cl- co transporter in ascending loop of Henle. Inhibits, increasing retention and thus increasing the volume of urine produced.

Question 6

Why do loop diuretics cause hypokalemia?

Answer 6

• The cotransporters that they inhibit bring potassium into the blood, and so inhibition results in less potassium

Question 7

Describe the “ceilings” of loop and thiazide diuretics

Answer 7

• Loop: high-ceiling
• Thiazide: lower ceiling

Question 8

List two thiazide diuretics

Answer 8

• Hydrochlorothiazide
• Chlorthalidone

Question 9

What do thiazide diuretics act on?

Answer 9

Na+K+/2Cl- cotransporters in DCT

Question 10

Mineralocorticoid inhibitor mech

Answer 10

• Bind to mineralocorticoid receptor in collecting ducts
• Prevent action of mineralocorticoids such as aldosterone

Question 11

List two common mineralocorticoid antagonists

Answer 11

• Spironolactone
• Epleronone

Question 12

Think: why do mineralocorticoids preserve potassium, when loop diuretics and thiazide diuretics don’t?

Question 13

Name two potassium sparing diuretics

Answer 13

• Amiloride
• Triamterine

Question 14

Potassium sparing diuretics mech

Answer 14

• Inhibits Na/K+ exchange in distal nephron