K+ sparing Diuretics

Question 1

what is the site of action of K+ sparing Diuretics ?

Answer 1

Collecting Duct

Question 2

what are the two types of cells found in the collecting ducts ?

Answer 2

Principal cells
the main Na+ reabsorbing cells and the site of action of aldosterone, K+-sparing diuretics, and spironolactone.

they secrete K+ through an apical membrane potasium channel.

α-intercalated cells
cells which contain apical H+ ATPase, explaining its ability to secrete protons.

Question 3

Name the K+ sparing Diuretics

Answer 3

Amiloride
(“Almonds”)

Triamterene
(“Tangerines”)

Eplerenone
(“apple with the teacher”)

Spironolactone
(“inspector with spiral bound notebook”)

Question 4

Aldosterone MOA

Answer 4

• upregulates ENaCs on the apical membrane
• upregulates Na+/K+ ATPse on the basolateral membrane
• upregulates K+ channels on the apical membrane
• upregulates H+ ATPase apical membrane

Question 5

K+ sparing Diuretics MOA

Answer 5

Amiloride , Triamterene

ENaC inhibition

Spironolactone , Eplerenone

Aldosterone receptor antagonists

Question 6

what are Amiloride and Triamterene used for ?

Answer 6

-useful in treatment of Li+ induced nephrogenic Diabetes insipidus
(“inspidus fountain in the background”)

-Amiloride and Triamterene are useful in the treatment of Liddles syndrome (overactive ENaCs)

(“Little midget blocked by tangerines and almonds carts”)

Question 7

what can Spironolactone and Eplerenone be used for ?

Answer 7

-useful in the treatment of primary and secondary Hyperaldosteronism, Conn syndrome, ACTH
(“Crumbling Mineral Mountain in the background”)

• useful in the treatment of heart failure to prevent K+ wasting
• prevent myocardial remodeling induced by high level of aldosterone

Question 8

at higher doses Spironolactone can ..

Answer 8

-is a synthetic steroid inhibit Androgen receptors , more specifically 17-alpha Hydroxylase enzyme thus lowers testosterone levels in the body

(“17 alpha-fry-droxylase” “fried male symbol)

• may treat symptoms of androgen excess in PCOS such as Hirsutism (“bubbling ovary fryers”)​

Question 9

what are the side effects seen with K+ sparing diuretics therapy ?

Answer 9

-can cause mild or even dangerous hyperkalemia
(“Elevated banana’s in stand”)

-may cause a normal anion gap metabolic acidosis
(by decreasing the function of the H+ATPase)

• K+ sparing diuretics inhibit the effects of aldosterone in the collecting duct causing a **type 4 renal tubular acidosis → **only one associated with hyperkalemia**.
• **

Question 10

possible side effects of Spironolactone

Answer 10

• inhibits androgen receptors and 17-alpha hydroxylase enzyme
• Gynecomastia (“hairy dudismo with lids on chest”)
• impotence and decreased libido (“Droopy churro”)

Question 11

What are two classes of diuretics which prevent cardiac remodeling and improve outcomes in heart failure?

Answer 11

(1) Aldosterone receptor antagonists

• Spironolactone
• ​Eplerenone

(2) ACE Inhibitors

• Capto , Lisino, Rami , Enala - PRIL