Spironolactone

Spironolactone — sold under the brand names Aldactone and CaroSpir — is a prescription medicine in a class called aldosterone antagonists. It was first developed as a "water pill" (a potassium-sparing diuretic) that helps the body release extra fluid and sodium while holding on to potassium. In that role it is used for high blood pressure, fluid build-up, and certain heart conditions.

What makes it relevant to women's hormone health is a second action: spironolactone also blocks androgens, the family of hormones (such as testosterone) that, in higher-than-usual amounts, can drive symptoms like unwanted hair growth and stubborn acne. By sitting on the receptors that androgens normally attach to, it can quiet these androgen-driven effects. That anti-androgen property is why it is sometimes prescribed off-label for people with PCOS (polycystic ovary syndrome).

"Off-label" means a clinician is using an approved medicine for a purpose that is well supported by research and clinical experience but is not written on the drug's official FDA label. This is legal and common, and it is always a decision made together with a prescriber who knows your history.

Spironolactone has two distinct jobs — a hormonal one and a fluid-balance one — so the reason one person takes it may be completely different from the next.

In midlife and hormone health, it is most often discussed for androgen-related skin and hair symptoms:

• Hirsutism — unwanted coarse hair in a male-type pattern, for example on the chin, jaw, chest, or abdomen. This is a common feature of PCOS; see our overview of PCOS symptoms.
• Hormonal acne — persistent breakouts, often along the jawline and chin, linked to androgen activity and sometimes slow to respond to standard acne treatments.
• Androgen-related hair thinning — some clinicians consider it for female-pattern scalp hair loss, though the evidence here is more limited.

Because these symptoms are so common in PCOS, spironolactone is one of several tools a clinician may weigh as part of a wider plan. You can read more in our guide to PCOS treatment and the broader PCOS guide.

Separately from its hormonal uses, spironolactone is FDA-approved for high blood pressure, swelling (edema) linked to heart, liver, or kidney conditions, heart failure, and a hormone disorder called primary hyperaldosteronism. These fluid- and pressure-related uses are managed on their own terms and are different from the skin-and-hair uses above.

Whether spironolactone is a sensible option depends on your whole picture — your symptoms, other health conditions, the other medicines and supplements you take, and whether pregnancy is possible. Only a prescriber can make that call for you.

Spironolactone must not be used during pregnancy. Because it blocks androgens, it can interfere with the normal development of a male fetus (a risk described as feminization). For that reason, clinicians usually prescribe it only alongside reliable contraception for anyone who could become pregnant, and it is stopped if pregnancy is planned or confirmed. Small amounts can also pass into breast milk, so breastfeeding is discussed case by case. Never start, stop, or change this medicine on your own — always work through your prescriber.

Spironolactone is taken by mouth — usually as a tablet, or as a liquid suspension in the case of CaroSpir. The dose, timing, and whether it is paired with other treatments are all decided by your prescriber based on why you are taking it and how you respond. For that reason this overview deliberately gives no numbers: the right amount is the amount your clinician has prescribed for you.

Some general principles that usually apply:

• Take it exactly as prescribed, and try to take it at the same time each day for a steady routine.
• Be consistent with food. Food can change how the liquid form is absorbed, so it helps to take it the same way (with or without food) each day, as your clinician or pharmacist advises.
• Give it time for skin and hair. When used for acne or hirsutism, benefits build gradually and often take several months to become noticeable — it is not a quick fix.
• Don't stop suddenly on your own, especially if you also take it for blood pressure; check with your prescriber first.
• Expect monitoring. Clinicians usually check blood potassium and kidney function with periodic blood tests, particularly when starting or adjusting the medicine.
• Be careful with potassium. Unless told otherwise, avoid potassium-based salt substitutes and high-dose potassium supplements, which can add to spironolactone's potassium-raising effect.

For acne or hirsutism, spironolactone is often prescribed together with a combined hormonal contraceptive. That combination can both help control androgen symptoms and provide the reliable pregnancy prevention that is essential while taking this medicine.

Most people tolerate spironolactone, but side effects do happen — many of them flow directly from how it works (moving fluid and blocking androgens). The ones below are relatively common and are often mild or settle with time, but you should report anything bothersome to your clinician.

This is not a complete list. Your pharmacist's leaflet and your prescriber can tell you what to expect for your situation.

The most important safety issue with spironolactone is that it can raise the level of potassium in your blood — a condition called hyperkalemia. Potassium is essential for a steady heartbeat, and levels that climb too high can, in serious cases, cause dangerous heart-rhythm problems. This is why clinicians monitor potassium with blood tests, and why the medicines and supplements you combine with it matter so much (see Interactions).

Hyperkalemia can be silent, but get urgent medical help if you notice:

• Unusual muscle weakness, heaviness, or fatigue
• Numbness or tingling
• A slow, pounding, or irregular heartbeat
• Trouble breathing, chest discomfort, or feeling faint

Other serious but less common concerns include significant dehydration or a sharp drop in blood pressure, changes in kidney function, and rare but serious allergic or skin reactions — for example a spreading rash, blistering, or swelling of the face, lips, or throat — all of which warrant prompt medical attention.

For transparency: the prescribing label notes that spironolactone caused tumors in rats given high doses over long periods in animal studies. Whether this has any bearing on humans at prescribed doses is not established, but the label advises against using the medicine when it is not needed. It is one more reason this is a clinician-guided decision rather than something to take casually.

Because spironolactone raises potassium, its most important interactions are with anything else that does the same. Share a complete list of what you take — including over-the-counter products and supplements — with your prescriber and pharmacist before starting.

Medicines and products that can add to the potassium-raising effect, or otherwise interact, include:

• Other blood-pressure medicines that affect potassium, such as ACE inhibitors and ARBs, and other potassium-sparing diuretics
• Potassium supplements and potassium-based salt substitutes
• NSAID pain relievers (for example ibuprofen and naproxen), which can affect both potassium and kidney function
• Certain antibiotics, such as trimethoprim, and the blood thinner heparin
• Lithium, whose levels can rise, and digoxin, a heart medicine that needs careful handling alongside spironolactone

Alcohol and other blood-pressure-lowering medicines can add to dizziness or low blood pressure. None of this means these combinations are always off-limits — many are used together safely under supervision — but they are reasons your clinician monitors you and adjusts the plan as needed.

This overview was written and edited by the VidaBeacon Editorial Team for general education. It is not medical advice and has not been individually reviewed for your circumstances. Spironolactone is a prescription medicine; decisions to start, stop, or change it should always be made with your own clinician or pharmacist.