Aldosterone Receptor Antagonist Diuretics in the treatment of congestive heart failure

Introduction

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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. 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[1]. Because of this, they are called potassium-sparing diuretics.[2]

They have a high affinity for the aldosterone receptor in the kidneys[3]. Blocking the aldosterone receptor prevents an increase in aldosterone, ultimately preventing changes to the cardiovascular system and allowing for increased water excretion. Aldosterone is a factor involved in cardiac hypertrophy and fibrosis and myocardial cell death thus has effects on myocardial remodelling. Evidence for a direct vascular effect of aldosterone suggests that this hormone may contribute to generalized vasoconstriction. Elevated plasma aldosterone levels can also contribute to depression of baroreflex sensitivity.[4]

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

[5]

Common ARAs

Two common aldosterone receptor antagonists are[6]

  • Spironolactone: taken orally with doses of 12.5-25 mg per day and has a long half-life of 13-17 hours[7].
  • Eplerenone is also taken orally with doses of 50 mg twice daily with a half-life of 4 hours[8] and both are excreted by via the liver and kidneys[9].

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[6].

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) Hence is it important to check for any irregular heartbeats if the patient begins complaining of chest pains or shortness of breath[10].

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.

References

  1. Nagarajan V, Chamsi-Pasha M, Tang WH. The role of aldosterone receptor antagonists in the management of heart failure: an update. [Review]. Cleveland Clinic Journal of Medicine. 2012;79(9):631-9.
  2. University of Michigan Aldosterone Receptor Antagonists: Diuretics for Heart Failure Available from: https://www.uofmhealth.org/health-library/tx4152 (last accessed 18.6.2019)
  3. Seawell MR, Al Darazi F, Farah V, Ramanathan KB, Newman KP, Bhattacharya SK, Weber KT. Mineralocorticoid receptor antagonism confers cardioprotection in heart failure. [Review]. Current Heart Failure Reports. 2013;10(1):36-45.
  4. Weber KT. Aldosterone in congestive heart failure. New England Journal of Medicine. 2001 Dec 6;345(23):1689-97. Available from: https://www.ncbi.nlm.nih.gov/pubmed/8682070 (last accessed 18.6.2019)
  5. Study Rx Aldosterone Receptor Antagonist - Spironolactone Available from: https://www.youtube.com/watch?v=XrOcp5FFvbI (last accessed 18.6.2019)
  6. 6.0 6.1 Lainscak M, Pelliccia F, Rosano G, Vitale C, Schiariti M, Greco C, Speziale G, Gaudio C (2015). Safety profile of mineralocorticoid receptor antagonists: Spironolactone and eplerenone. Int J Cardiol. 200, 25-9
  7. U.S. Food and Drug Administration (FDA). Aldactone spironolactone tablets, USP. Available online at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2008/012151s062lbl.pdf. Last accessed 11/29/18.
  8. U.S. Food and Drug Administration (FDA). INSPRA eplerenone tablets. Available online at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2002/21437lbl.pdf. Last accessed 11/29/18.
  9. Nappi JM, Sieg A (2011). Aldosterone and aldosterone receptor antagonists in patients with chronic heart failure. Vasc Health Risk Manag. 7, 353-63.
  10. Sica DA. Diuretic-related side effects: development and treatment. J Clin Hypertens. 2004;6:532–540.