(2'R,7R,8R,9S,10R,13S,14S)-10,13-Dimethyl-3,5',18-trioxooctadecahydro-3'H-spiro[4,7-methanocyclopenta[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.