Potassium Sparing Diuretics

Question 1

two potentially useful responses

Answer 1

1) produce a modest increase in urine production
2) produce a substantial decrease in potassium excretion

Question 2

are potassium-sparing diuretics given on their own?

Answer 2

No, because their diuretic effects are limitted

Question 3

Why are potassium-sparing diuretics used in combination with thiazide and loop diuretics?

Answer 3

They have a marked ability to decrease potassium excretion, so they are used to counteract potassium loss caused by thiazide and loop diuretics.

Question 4

two subcategories of potassium-sparing diuretics

Answer 4

aldosterone antagonists & nonaldosterone antagonists

Question 5

What aldosterone antagonist is used for diuresis

Answer 5

Spironolacetone

Question 6

Spironolacetone- mechanism of action

Answer 6

-blocks actions of aldosterone in the distal nephron causing retention of potassium, and increased excretion of sodium.
(aldosterone acts to promote sodium uptake in exchange for potassium excretion)
-the diuresis caused by spironolacetone is scanty because most of the filtered sodium load has already been reabsorbed by the time the filtrate reaches the distal nephron.
-delayed response (48 hours)

Question 7

Spironolacetone therapeutic uses

Answer 7

-hypertension and edema (usually in combo with thiazide or loop diuretic)
-heart failure

Question 8

Spironolacetone adverse effects

Answer 8

-hyperkalemia
-endocrine effects because it is a steroid
derivative with a similar structure to that of steroid hormones (gynecomastia, menstrual irregularities, impotence, hirsutism, deepening of voice)
-benign and malignant tumours