(2'R,7R,8R,9S,10R,13S,14S)-18-Amino-10,13-dimethyl-3,5'-dioxo-2,3,4',5,5',6,7,8,9,10,11,12,13,14,15,16-hexadecahydro-1H,3'H-spiro[4,7-(metheno)cyclopenta[a]phenanthrene-17,2'-furan]-5-carbonitrile is an intermediate in synthesizing Mexrenone (). It is an impurity of eplerenon (E588775). Eplerenone is a selective aldosterone receptor antagonist (SARA), structurally similar to Spiranolactone. Eplerenone is used alone or in combination with other medications to treat high blood pressure. Eplerenone is in a class of medications called mineralocorticoid receptor antagonists. It works by blocking the action of aldosterone, a natural substance in the body that raises blood pressure.