Spironolactone—a potassium-sparing diuretic, or “water pill”—has been used to treat hypertension for nearly 60 years. But this venerable drug does more than just flush water and sodium out of the system to lower blood pressure. About 20 years ago, investigators found that spironolactone had another ability as a therapy for heart failure.
Over the years, researchers have discovered that this water pill has a variety of uses. It not only reduces hypertension and risk of heart failure, but treats acne, hair loss, hirsutism, and other conditions. Let’s look at its many applications.
In the landmark Randomized Aldactone Evaluation Study (RALES), researchers reported that spironolactone treatment (in addition to standard angiotensin-converting–enzyme [ACE] inhibitor therapy) substantially reduced the risk of death, morbidity, and hospitalization in patients with severe heart failure. Spironolactone also improved the symptoms of heart failure. In addition, at the low 25-mg dose used in this study, spironolactone resulted in few serious cases of elevated potassium (hyperkalemia).
Ascites due to cirrhosis
Ascites (accumulation of fluid in the abdomen) is the most common complication of liver cirrhosis. In addition to abstaining from alcohol and restricting sodium in the diet, first-line therapy for patients with ascites involves once-daily doses of spironolactone 100 mg and furosemide 40 mg. The doses of both diuretics can be increased every few days until reaching a maximum of 400 mg per day of spironolactone and 160 mg per day of furosemide, according to the American Association for the Study of Liver Diseases.
Female pattern hair loss
Spironolactone is a steroid that blocks specific male hormones in both men and women. It’s used more commonly in women because male patients who take spironolactone may experience gynecomastia (enlargement of breast tissue), loss of libido, and general feminization.
Female pattern hair loss—a problem that affects about 40% of women by age 50—is caused by androgenic alopecia, which is associated with overproduction of androgen hormones in women. Spironolactone has anti-androgenic effects to inhibit these hormones. In one study, 74.3% of patients taking spironolactone reported stabilization or improvement of their female pattern hair loss. Note that minoxidil is considered the first-line treatment for female pattern hair loss, and spironolactone is usually only prescribed when patients don’t respond to minoxidil.
Hirsutism in women
Hirsutism—characterized by excess hair growth on the face or body—affects 5% to 10% of women. Like female pattern hair loss, hirsutism in women is usually the result of excess androgen production. Although oral contraceptives are first-line therapy for the treatment of hirsutism, researchers have shown that oral contraceptives plus spironolactone are better than oral contraceptives alone. The Endocrine Society recommends that all women who have signs of hirsutism be tested for elevated androgen levels, as 70% to 80% of women with hirsutism have polycystic ovary syndrome.
Hyperaldosteronism occurs when the adrenal glands overproduce aldosterone. It’s characterized by hypertension that doesn’t respond to standard blood pressure therapy. Hyperaldosteronism is commonly caused by a benign adrenal tumor or by bilateral adrenal hyperplasia. Treatment for benign adrenal tumor involves laparoscopic adrenalectomy. Patients with bilateral adrenal hyperplasia are treated with spironolactone, or another an aldosterone antagonist, and put on a low-salt diet.
Acne in women
Although spironolactone has been investigated for 25 years as an acne treatment, many dermatologists continue to consider it as an alternative therapy for women with acne rather than a primary one. However, researchers have shown that spironolactone treatment clears acne on the face, chest, and back for a large percentage of women, with low rates of relapse and discontinuation of therapy.
High blood pressure
As a treatment for hypertension, spironolactone has largely been replaced by more modern, first-line thiazide diuretics; however, spironolactone is still used in conjunction with other diuretics for high blood pressure.
As noted above, spironolactone is not without serious adverse effects, including gastritis, hyperkalemia, gynecomastia in men, and breast pain. Women who are pregnant or trying to get pregnant shouldn’t take spironolactone because its anti-androgenic effects pose potential risk to a male fetus.
Less severe side effects include drowsiness, lethargy, confusion, headache, fever, ataxia, fatigue, anorexia, dyspepsia, nausea, vomiting, peptic ulceration, and colic. To reduce the risk of gastric irritation, advise patients to take spironolactone with food.