Mineralocorticoid Receptor Antagonists

Question 1

Class of Spironolactone and Eplerenone

Answer 1

Diuretic - K+ sparing diuretic steroid; mineralocorticoid receptor (MR) and aldosterone receptor antagonist

Question 2

MOA of Spironolactone and Eplerenone

Answer 2

Mineralocorticoid receptor (MR) + aldosterone receptor antagonist –> inhibits aldosterone induced expression of Na channels (ENaC) and Na/K ATPase –> reduced Na/H2O retention and decreased K, H+ excretion (how it’s used for diuresis) AND –> inhibits androgen synthesis (how it’s used for prostate cancer)

Question 3

Tx w/Spironolactone and Eplerenone

Answer 3

Primary and secondary hyperaldosteronism; HTN; hormonal tx for prostate cancer

Question 4

Toxicity/SE of Spironolactone and Eplerenone

Answer 4

Androgen receptor antagonist so SE includes gynecomastia, impotence –> less so w/ eplerenone; hyperkalemia; metabolic acidosis, GI

Question 5

Drug Interactions of Spironolactone and Eplerenone

Answer 5

ACE (angiotensin-converting enzyme) inhibitor/angiotensin receptor blocker (ARBs) –> hyperkalemia