Mineralocorticoid receptor antagonist

Question 1

Mineralocorticoid receptor antagonist - examples

Answer 1

Spironolactone

Eplerenone

Question 2

Mineralocorticoid receptor antagonist - indication

Answer 2

Chronic heart failure
(Usually in addition to Beta blocker and ACEi/ARB)

Ascites and oedema due to liver cirrhosis
Spironolactone is the first line diuretic used

Primary hyperaldosteronism
For patients awaiting surgery or where surgery is not an option

Resistant hypertension
Add on treatment when other anti-hypertensive medications are not sufficient (e.g.- calcium channel blockers, ACE inhibitors, thiazide diuretics)

Question 3

Mineralocorticoid receptor antagonist - MOA

Answer 3

1) Competitively bind to aldosterone receptor
2) Reduces action of aldosterone
3) increasing Na+/H2O excretion and K+ retention

Question 4

Mineralocorticoid receptor antagonist - adverse effects

Answer 4

→ Hyperkaliemia which can lead to muscle weakness, arrhythmias and even cardiac arrest

→ Spironolactone causes gynecomastia
Warn men about possibility of growth and tenderness of tissue under the nipple and impotence - reassure them that these effects are reversible but acknowledge that it may be uncomfortable and embarrassing

→ Can cause liver impairment and jaundice

Question 5

Mineralocorticoid receptor antagonist - interactions

Answer 5

→ Avoid use with potassium elevating drugs including ACEi and ARB
Why?
Increase risk of hyperkalaemia

→ Should NOT be used with potassium supplements

Question 6

Mineralocorticoid receptor antagonist - contraindicated (avoid)

Answer 6

→ Severe renal impairment
→ Hyperkaliemia
→ Addison’s disease

Question 7

Mineralocorticoid receptor antagonist (caution)

Answer 7

Avoid use when possible in pregnant or lactating women

why? can cross the placenta and appear in breast milk