Eplerenone is a selective mineralocorticoid receptor inhibitor. It has no affinity for glucocorticoid, progesterone and androgen receptors and therefore has lower risk of side effects. Eplerenone lowers blood pressure and inhibits heart muscle fibrosis. The hypotensive effect is caused by reduction of fluid retention. Probably, in patients with OSA, a reduction of fluid accumulation especially at the level of the neck may contribute to lowering the resistance in the upper respiratory tract and in that way it may help to decrease the severity of OSA.