Aldactone tablet is also known as spironolactone. Each aldactone tablet contains spironolactone as active ingredient. Spironolactone is also known as water pill. This medication is used in the treatment of high blood pressure. It is also used in the treatment of edema (swelling) caused by congestive heart failure by removing excess fluid and improving breathing problems. Aldactone is also used to treat low potassium levels.