Spironolactone: what it treats, how to take it, side effects
Last updated September 3, 2026.
Spironolactone is a diuretic that removes water and sodium while keeping potassium in your body. You may know it as Aldactone. That potassium-sparing trick is exactly what makes it useful - and exactly what demands respect: too much potassium is the danger direction.
What does it treat?
Too much aldosterone (hyperaldosteronism), low potassium, heart failure, fluid retention from liver or kidney disease, and - alone or with other medications - high blood pressure. It is also widely used off-label for hormonal acne in women, which is a doctor's-call conversation. MedlinePlus carries a standing warning that spironolactone caused tumors in laboratory animals - talk to your doctor about the risks and benefits for your situation.
How do you take it?
Once or twice a day, same times every day. If you take the liquid (Carospir), be consistent: always with food or always without, and shake it well. Tablets and liquid release differently and cannot be substituted for each other - take only the product prescribed. Your doctor may start low and increase gradually. Full effect takes about 2 weeks or longer. Keep taking it even when you feel well, and never stop without your doctor. Missed dose: take it when you remember unless the next one is close; never double up.
Side effects to know
- Common: vomiting, diarrhea, stomach pain or cramps, enlarged or painful breasts in men or women, irregular periods, vaginal bleeding after menopause, erection difficulty, deepening of the voice, increased body hair, drowsiness, tiredness, and restlessness.
- Serious - the high-potassium cluster: muscle weakness, pain, or cramps; pain, burning, numbness, or tingling in hands or feet; inability to move arms or legs; changes in heartbeat; confusion; nausea; and extreme tiredness. Also serious: dehydration signs (dry mouth, thirst, dizziness, unsteadiness, headache), unusual bleeding or bruising, lack of energy, loss of appetite, and upper right stomach pain. Call your doctor immediately.
Who should not take it?
Anyone with Addison's disease, high potassium, or kidney disease - MedlinePlus says your doctor may rule it out. The everyday rules are potassium rules: avoid potassium-containing salt substitutes, talk to your doctor about how much potassium-rich food (bananas, prunes, raisins, orange juice) fits your diet, and flag potassium supplements and NSAIDs like ibuprofen and naproxen, which interact. Expect periodic blood tests - that is how potassium gets watched. Pregnancy and breastfeeding need a direct call.
When is it an emergency?
Muscle weakness with an irregular heartbeat, inability to move an arm or leg, or fainting is a 911 call - that is the high-potassium emergency. For an overdose, call Poison Control at 1-800-222-1222. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Why can't I use salt substitutes on spironolactone?
Because most salt substitutes are potassium chloride. MedlinePlus says to avoid potassium-containing salt substitutes while taking spironolactone - the drug already keeps potassium in your body, and adding more on top can push levels into the dangerous zone: muscle weakness, heartbeat changes, in severe cases paralysis. Regular salt in moderation, per your doctor's diet plan.
Why do I need blood tests on spironolactone?
To watch the potassium. Spironolactone's whole mechanism is keeping potassium in, and the only way to know it has not overshot is a blood test - especially after starting, after dose changes, and if you get dehydrated or sick. Muscle weakness, tingling, or a changed heartbeat between tests means calling your doctor, not waiting for the next one.
Why is spironolactone prescribed for acne?
It blocks androgen hormones, which drive hormonal acne along the jawline and chin in women. That is an off-label use - the labeled uses are heart failure, blood pressure, fluid retention, high aldosterone, and low potassium - and the breast tenderness and period changes on the side effect list come from the same hormone effect. Whether it fits you is a dermatologist or doctor decision.
Can I take ibuprofen while on spironolactone?
Flag it first. MedlinePlus says NSAIDs like ibuprofen and naproxen may interact with spironolactone and says not to start them without discussing with your healthcare provider - the combination stresses the kidneys and pushes potassium up. For routine pain relief, ask your doctor what to use instead.
What is the tumor warning about?
MedlinePlus carries the warning verbatim: spironolactone has caused tumors in laboratory animals, and you should talk to your doctor about the risks and benefits for your condition. It is a caution label, not a proven human cancer link - but it is exactly the kind of thing to raise directly at the prescribing visit.
Can I drink alcohol while taking spironolactone?
Neither the label nor MedlinePlus gives spironolactone-specific alcohol language. Alcohol dehydrates and drops blood pressure, and both interact with what a diuretic does. Keep it light, keep the fluids up, and get the personal rule from your doctor.