Spironolactone is a medication that primarily acts as a potassium-sparing diuretic, commonly used to treat conditions such as heart failure, high blood pressure, and certain cases of edema. It works by blocking the actions of aldosterone, a hormone that promotes sodium retention and potassium excretion, leading to increased urine production and reduced fluid retention. Additionally, spironolactone is sometimes used for hormonal imbalances, such as in the treatment of polycystic ovary syndrome (PCOS) and acne. It is important to monitor potassium levels while using this medication due to its potassium-sparing effects.