CARDIO: ALDOSTERONE AGONISTS

Question 1

ALDOSTERONE ANTAGONISTS: INDICATIONS

Answer 1

• Ascites or oedema due to liver cirrhosis (Spir 1st line)
• CHF - as an addition to beta blocker + ACE inhib/ARB
• Primary Hyperaldosteronism

Question 2

ALDOSTERONE ANTAGONISTS: MOA

Answer 2

Aldosterone mineralocorticoid produced in the adrenal cortex, acts on mineralocorticoid receptor in the distal tubules to increase the activity of the EPITHELIAL SODIUM CHANNELS (ENaC. Increases reabsorption of sodium and water, with the by product of increased pottasium excretion)

• Inhibit the effect of aldosterone, by competitively binding to the aldosterone receptor => increases sodium and water reabsorption and potassium excretion
• Greatest in primary hyperaldosteronism or when circulating aldosterone is increased (eg in cirrhosis)

Question 3

ALDOSTERONE ANTAGONISTS: ADVERSE EFFECTS

Answer 3

• Hyperkalaemia = muscle weakness, arrhythmias and cardiac arrest in extreme cases
• Gynaecomastia
• Liver impairment and jaundice (Steven-Johnson syndrome) = bullous skin eruption

Question 4

ALDOSTERONE ANTAGONISTS: WARNINGS

Answer 4

• Severe renal impairment
• Hyperkalaemia
• Addisons Dx
• AA can cross the placenta during pregnancy and appear in breast milk so should be avoided where possible in PREGNANT/LACTATING WOMEN

Question 5

ALDOSTERONE ANTAGONISTS: INTERACTIONS

Answer 5

• Pottassium elevating drugs (ACE Inhibs and ARBs)

- Do not combine with pottassium supplements