Spironolactone (宿, BAN, ウーサン) commonly referred to simply as spiro, and marketed primarily under the brand name Aldactone in most countries, is a synthetic, steroidal antimineralocorticoid and antiandrogen that also has some weak progestogen properties, as well as some indirect estrogen and glucocorticoid effects. It is used primarily as a diuretic and antihypertensive, but may also be employed for the purpose of reducing elevated or unwanted androgen activity in the body. It acts predominantly as an antagonist of the mineralocorticoid (or aldosterone) and androgen receptors, and in relation to its antimineralocorticoid effects, belongs to a class of pharmaceutical drugs known as potassium-sparing diuretics.
Spironolactone is used primarily to treat heart failure, edematous conditions such as nephrotic syndrome or ascites in patients with liver disease, essential hypertension, hypokalemia, secondary hyperaldosteronism (such as occurs with hepatic cirrhosis), and Conn's syndrome (primary hyperaldosteronism). On its own.
Because spironolactone reduces the body's production of testosterone and blocks the androgen receptors, it can cause effects associated with low testosterone levels and hypogonadism in males. For this reason, men are typically not prescribed spironolactone for any longer than a short period of time, e.g. for an acute exacerbation of heart failure. The newer drug, eplerenone has been approved by the U.S. Food and Drug Administration for treatment of heart failure, but lacks the rather potent antiandrogen effects and thus is far more suitable for men for whom long term medication is being chosen. Unlike with some other diuretics, potassium supplementation should not be administered while taking spironolactone as this may cause dangerous elevations in serum potassium levels resulting in hyperkalemia and potentially deadly cardiac arrythmias. Physicians must be careful to monitor potassium levels in both males and females who are taking spironolactone, especially during the first twelve months of use and whenever the dosage is increased.
