Aldactone (Spironolactone): Uses, Potassium and Safety

What Aldactone is used for

Aldactone contains spironolactone, an aldosterone blocker and potassium-sparing diuretic. It helps remove excess fluid while affecting how the kidneys handle potassium. Uses include selected heart-failure patients, resistant high blood pressure, certain liver- or kidney-related fluid retention, and excess aldosterone production. This summary concerns the 25 mg oral tablet. These conditions require different treatment plans, so the strength alone does not identify why a person was prescribed it.

What to expect and discuss

Swelling caused by retained fluid may affect the feet, ankles or other body areas. Treatment is prescribed for the underlying condition rather than for every kind of swelling. Follow the instructions for the actual product; the US label advises a consistent relationship with food. Keep scheduled blood tests and clinical reviews. Ask a pharmacist about problems taking the tablets rather than changing the medicine on the basis of swelling or body weight alone.

Side effects and warning signs

Dizziness, nausea, tiredness, cramps, and breast discomfort or enlargement can occur. Spironolactone can also cause dangerously high potassium, particularly with kidney problems or interacting medicines. Marked weakness, an abnormal heartbeat, fainting or much less urine needs prompt assessment. Breathing difficulty or tongue or throat swelling may be an emergency allergic reaction. The US label contraindicates Aldactone in hyperkalaemia, Addison disease and concurrent eplerenone use.

Interactions and monitoring

Potassium supplements and potassium-containing salt substitutes should not be added without a medicine review. ACE inhibitors, ARBs, trimethoprim and some other medicines can increase potassium further; combinations may require close testing. NSAIDs can reduce the diuretic and blood-pressure response and add kidney-related concerns. Lithium toxicity is another important interaction. Spironolactone can interfere with some digoxin blood assays, so a laboratory result does not always mean that true drug exposure increased. Inform clinicians about supplements and nonprescription painkillers.

Pregnancy, breastfeeding and information scope

Animal findings raise concern about effects on male fetal sexual development, so pregnancy requires prompt specialist discussion rather than assuming the medicine is safe. A breastfeeding decision should consider the infant, available evidence and treatment need. The main medicine-specific source is the US Aldactone label, supplemented by NHS patient guidance. Other countries may license additional uses; this summary does not establish approval for those uses or provide an individual dosing plan.

Sources

• Aldactone oral tablets: US product information — US prescribing information revised November 2025; SPL version 25, effective 28 November 2025
• NHS guidance on spironolactone — Patient medicine guidance; checked 30 October 2026

Source check: 30 October 2026. This records a source check, not a clinical review by a doctor or pharmacist. Use the current leaflet supplied with your medicine and seek qualified advice for personal treatment.