Spironolactone (Aldactone)

  • Generic name: Spironolactone ("spiro")
  • Brand names: Aldactone, Novo-Spiroton, Spiractin, Spirotone, Verospiron, Berlactone
  • Drug class: Potassium-sparing Diuretic, Aldosterone antagonist
  • Pregnancy Category C

What is Spironolactone used for?

  • Diagnosis and treatment of hyperaldosteronism, a condition in which the adrenal gland secretes too much aldosterone (a hormone that regulates the body's salt and potassium levels).
  • Treatment of conditions that require the elimination of excess fluid from the body, including congestive heart failure, high blood pressure, liver cirrhosis, kidney disease, and unusually low potassium levels in the blood. The diuretic effect is seen within 48 hours.
  • Hirsutism (unwanted facial hair) in women with polycystic ovary syndrome or idiopathic hirsutism.
  • Acne in women.


  • Urination problems: anuria (passage of less than 50 mL of urine in a day), significant impairment of renal excretory function
  • Renal insufficiency
  • Hyperkalemia (high levels of potassium in the blood)
  • Do not use potassium supplements or other diuretics while you are taking spironolactone. High potassium levels may cause potentially fatal cardiac irregularities.


  • Gynecomastia. Spironolactone may induce gynecomastia (breast enlargement in men) by decreasing testosterone production, increasing peripheral conversion of testosterone to estradiol, and displacing estradiol from sex hormone-binding globulin. Dosages higher than 150 mg per day have been associated with up to a 52% prevalence of gynecomastia3. Usually, the breast enlargement goes away after discontinuation of treatment.
  • Hyperkalemia. Spironolactone may raise serum potassium levels and cause hyperkalemia, which can result in fatal cardiac irregularities. The risk of hyperkalemia is higher in patients with heart failure, impaired renal function, and excessive potassium intake.
  • Menstrual abnormalities have been reported in 18% of patients on on low-dose spironolactone (50-100 mg daily) and 70% of those on 200 mg daily. Spironolactone frequently causes irregular spotting or bleeding between menstrual periods4. Also, it may cause post-menopausal bleeding, menstrual cycle irregularities, and stopping periods altogether (amenorrhoea).
  • Spironolactone may worsen glycaemic control in patients with diabetes2.

Serious drug interactions

  • Lithium: reduced renal clearance of lithium and increased risk of toxicity.
  • NSAIDs, Cyclosporine, Tacrolimus, ACE inhibitors: increased risk of hyperkalemia, use with caution.
  • Potassium supplements: increased risk of hyperkalemia; concomitant use generally not recommended.
  • Potassium-sparing diuretics (e.g. amiloride, triamterene): concomitant use contraindicated.

Dietary considerations

Avoid potassium-containing salt substitutes. Limit your intake of potassium-rich foods (e.g., bananas, orange juice, dried fruits). Consuming these foods is usually safe but do not consume excessive amounts.

Spironolactone is best absorbed if taken with food.

Spironolactone alternatives

Medications that can be used instead of Spironolactone:

  • Eplerenone (Inspra), another aldosterone-blocking agent and potassium-sparing diuretic, is an effective alternative for spironolactone in the treatment of hypertension and heart failure5. Eplerenone is very similar to spironolactone, but does not possess any antiandrogen, progestogen, or estrogenic effects.
  • Metformin (Glucophage), an insulin sensitizer, may improve ovarian function and hirsutism in women with PCOS.
  • Cyproterone acetate (CPA), usually in combination with ethinyl estradiol (Diane-35), is frequently used to treat hirsutism and acne.
  • Furosemide (Lasix), a loop diuretic, is used to treat hypertension and edema. The combination of spironolactone with furosemide (usual ratio 100:40) is used in liver cirrhosis with ascites to maintain normal electrolyte balance.
  • Triamterene (Dyrenium), a potassium-sparing diuretic, may be used instead of spironolactone to treat hypertension and edema.


  • 1. Spironolactone Monograph Reference guide from the American Society of Health-System Pharmacists.
  • 2. Swaminathan K, Davies J, George J, Rajendra NS, Morris AD, Struthers AD. Spironolactone for poorly controlled hypertension in type 2 diabetes: conflicting effects on blood pressure, endothelial function, glycaemic control and hormonal profiles. Diabetologia. 2008 May;51(5):762-8.
  • 3. Haynes BA, Mookadam F. Male gynecomastia. Mayo Clin Proc. 2009 Aug;84(8):672.
  • 4. Helfer EL, Miller JL, Rose LI. Side-effects of spironolactone therapy in the hirsute woman. J Clin Endocrinol Metab. 1988 Jan;66(1):208-11.
  • 5. Futterman LG, Lemberg L. The resurrection of spironolactone on its golden anniversary. Am J Crit Care. 2004 Mar;13(2):162-5.

Last updated: May, 2015

Good to know

aldactone 25 mg
  • Reasons to choose Spironolactone:
  • First-line therapy for hirsutism in women with PCOS. Spironolactone is very effective, but not FDA-approved for this use.
  • Spironolactone is suitable for women whose acne is refractory to antibiotics and other standard treatments.
  • Spironolactone is more effective in conditions associated with high circulating levels of aldosterone.