Spironolactone
Aldactone is the brand-name spironolactone tablet in 25 mg, 50 mg and 100 mg strengths, used for Hypertension, Heart Failure and fluid retention from liver or kidney disease.
Key points
- Unlike most diuretics, spironolactone is potassium-sparing: it blocks aldosterone so the body keeps potassium rather than flushing it out.
- Hyperkalaemia (high potassium levels) is the main risk: avoid potassium supplements, salt substitutes and potassium-rich foods like bananas while taking it.
- Spironolactone controls high blood pressure, heart failure and fluid retention but does not cure these conditions; the full effect may take about two weeks.
How does Spironolactone work?
Spironolactone works by blocking aldosterone, a hormone that tells the kidneys to hold on to sodium and water while releasing potassium. When aldosterone is blocked, the kidneys pass more sodium and water into the urine, which lowers blood volume and eases the strain on the heart. Because potassium is retained rather than lost, spironolactone behaves differently from most other diuretics in the Heart & Blood Pressure range. This potassium-sparing action is why the main safety concern is hyperkalaemia rather than the low potassium that other diuretics cause.
Further reading
What is spironolactone used for?
Spironolactone is used for high blood pressure, heart failure and fluid retention from liver or kidney disease. It controls these conditions but does not cure them.
What does spironolactone do in the body?
Spironolactone blocks aldosterone, a hormone that tells the kidneys to hold on to sodium and water while releasing potassium. This causes the kidneys to pass more sodium and water into the urine, which lowers blood volume and eases the strain on the heart.
How long does spironolactone take to work?
Spironolactone starts to work within 2 to 3 days, but the full effect may take about two weeks.
What are the side effects of spironolactone?
Common side effects include headache, nausea and dizziness. Other effects can include gynaecomastia, hyperkalaemia and electrolyte imbalance, while severe hyperkalaemia and anaphylaxis need immediate medical attention. Speak to your doctor or pharmacist if you are concerned.
Can spironolactone be taken with other medicines?
Spironolactone can interact with ACE inhibitors, potassium supplements and NSAIDs. If you take any of these, ask your doctor or pharmacist before using spironolactone.
In which products can I find spironolactone?
On Direct Meds, spironolactone comes as Aldactone. Compare their forms, strengths and packs.
How much does spironolactone cost in South Africa?
Compare the rand prices for each product, strength and pack above. Prices are converted from US dollars. Larger packs usually cost less per tablet.
Payment and prices →Do I need a prescription for spironolactone in South Africa?
No, not online. Direct Meds does not ask for a prescription to order spironolactone. We are a broker, not a dispensing pharmacy. We arrange orders and delivery with our affiliated supplier on your behalf.
Ordering without a prescription →Can I buy spironolactone online in South Africa?
Yes. Our affiliated supplier delivers across South Africa. Estimated delivery is 7 days with Express Delivery, which includes online tracking, or up to 3 weeks with Regular Delivery.
How ordering works →