Aldosterone Receptor Antagonist

Original Editor - Lauren Pulliam Southern Top Contributors - Lucinda hampton, Kim Jackson, Lauren Pulliam Southern and Beau Lawrence

Introduction

Aldosterone is a hormone secreted by the adrenal gland (zona glomerulosa). Aldosterone was classified as a mineralocorticoid hormone as it was found to play a major role in sodium reabsorption and potassium excretion. The primary action of aldosterone

1. Sodium and water retention
2. Also promotes myocardial fibrosis and induce cardiac hypertrophy and remodeling.
3. Can directly alter endothelial function by reducing nitric oxide availability and stimulating a vascular inflammatory response.

Aldosterone receptor antagonists (ARAs) are a type of diuretic used in patients with CHF. They also have other properties that can prevent heart failure from becoming worse, along with improving symptoms of heart failure. Aldosterone receptor antagonists are proven to be beneficial in heart failure patients even if they are already on angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs).  

• These medicines cause the kidneys to get rid of extra water and they help to retain potassium by inhibiting secretion of potassium into distal tubule of the nephron.

Because of this, they are called potassium-sparing diuretics.

Blocking the aldosterone receptor prevents an increase in aldosterone, ultimately preventing changes to the cardiovascular system and allowing for increased water excretion.

Most aldosterone receptor antagonists are used in conjunction with other medications, specifically Beta Blockers and Ace Inhibitors.

Common ARAs

Two common aldosterone receptor antagonists are

• Spironolactone: taken orally with doses of 12.5-25 mg per day and has a long half-life of 13-17 hours.

• Eplerenone is also taken orally with doses of 50 mg twice daily with a half-life of 4 hours and both are excreted by via the liver and kidneys.

Adverse Effects

Due to the prevention of potassium secretion into the distal tubule both these drugs are associated with an adverse effect of

• Hyperkalemia due to them being potassium sparing diuretics.

• Gynecomastia and breast pain in men because it tends to bind to progesterone and androgen receptors.

Physiotherapy - Implications

This drug, while acting to relieve the body of excessive fluids, can inadvertently disrupt the electrolyte and pH balance in the system. Because the main side effect is hyperkalemia, Hyperkalemia affects the cardiac conductive tissue and can cause serious arrhythmias ( eg ventricular fibrilllation, asystolic arrest).

• It important to check for any irregular heartbeats if the patient begins complaining of chest pains or shortness of breath.
• In addition to monitoring the patient’s vitals before, during and after treatment, patients should be educated on lifestyle changes to help decrease their mortality.