Q: Which of the following is the proposed mechanism of action causing beneficial effects of the aldosterone-receptor blocker (Spironolactone) in congestive heart failure?
A) Averting sodium retention
B) Averting myocardial fibrosis
C) Averting potassium loss
D) increasing the myocardial uptake of norepinephrine
E) All of the above
Mechanism of action of an aldosterone-receptor blocker is complex. Some effects are well known Like Choices A and C. Objective of the above question is to highlight their role by averting myocardial fibrosis (Choice B). It reduces the risk of sudden death from arrhythmias. Also, myocardial uptake of norepinephrine (choice D) has been demonstrated in the animal models.
1. Pitt B et al. The effect of spironolactone on morbidity and mortality in patients with severe heart failure. Randomized Aldactone Evaluation Study Investigators. N Engl J Med. 1999 Sep 2;341(10):709-17.
2. Buss SJ et. al. Spironolactone preserves cardiac norepinephrine reuptake in salt-sensitive Dahl rats. Endocrinology. 2006 May;147(5):2526-34.