Spironolactone

Key points

• Potassium and kidney function need monitoring because dangerous hyperkalaemia can develop.
• Potassium supplements, salt substitutes and several heart or kidney medicines can make combinations unsafe.
• Severe weakness, fainting or an irregular heartbeat needs urgent assessment.

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What Spironolactone is used for

It may be used for heart failure, hypertension, oedema or hyperaldosteronism. It also has selected anti-androgen uses under clinical care.

How it works

Spironolactone blocks mineralocorticoid receptors in the kidney and other tissues, reducing aldosterone-driven sodium retention and potassium loss.

Important safety checks

Kidney function, potassium, dehydration, pregnancy and interacting medicines require review. ACE inhibitors, ARBs, potassium products, trimethoprim and anti-inflammatory painkillers can increase risk. Breast or sexual changes can occur and should be discussed.

When to seek urgent care

Seek urgent help for severe muscle weakness, fainting, confusion, a slow or irregular heartbeat, very low urine output, facial swelling or breathing difficulty.

Further reading

• Spironolactone: MedlinePlus Drug Information
• Spironolactone - NHS
• Heart failure - causes, symptoms and treatment - BHF