Pharmacology: K+ sparing Diuretics

Question 1

describe the action of amiloride and triamterene K+ sparing diuretics

Answer 1

block the apical sodium channel and decrease Na+ reabsorption in collecting tubule

Question 2

describe the action of spironolactone and eplerenone K+ sparing diuretics

Answer 2

compete with aldosterone for binding to intracellular receptors preventing actions of steroids(Na reabsorption)

Question 3

describe spironolactone/eplerenone affect on Na and K

Answer 3

Na = increased excretion
K = decreased excretion

Question 4

describe how amiloride/triamterene enter the nephron

Answer 4

via organic cation transporter(OCT) system in proximal tubule

Question 5

describe the major use of K sparing diuretics

Answer 5

in conjunction with other agents that cause K loss

Question 6

if given alone what doe K sparing diuretics cause

Answer 6

hyperkalaemia

Question 7

what are the contraindications for K sparing diuretics

Answer 7

severe renal impairment, hyperkalaemia, Addison’s disease